§ 203. Method of computing periods of limitation generally. (a)
Accrual of cause of action and interposition of claim. The time within
which an action must be commenced, except as otherwise expressly
prescribed, shall be computed from the time the cause of action accrued
to the time the claim is interposed.

(b) Claim in complaint where action commenced by service. In an action
which is commenced by service, a claim asserted in the complaint is
interposed against the defendant or a co-defendant united in interest
with such defendant when:

1. the summons is served upon the defendant; or

2. first publication of the summons against the defendant is made
pursuant to an order, and publication is subsequently completed; or

3. an order for a provisional remedy other than attachment is granted,
if, within thirty days thereafter, the summons is served upon the
defendant or first publication of the summons against the defendant is
made pursuant to an order and publication is subsequently completed, or,
where the defendant dies within thirty days after the order is granted
and before the summons is served upon the defendant or publication is
completed, if the summons is served upon the defendant's executor or
administrator within sixty days after letters are issued; for this
purpose seizure of a chattel in an action to recover a chattel is a
provisional remedy; or

4. an order of attachment is granted, if the summons is served in
accordance with the provisions of section 6213; or

5. the summons is delivered to the sheriff of that county outside the
city of New York or is filed with the clerk of that county within the
city of New York in which the defendant resides, is employed or is doing
business, or if none of the foregoing is known to the plaintiff after
reasonable inquiry, then of the county in which the defendant is known
to have last resided, been employed or been engaged in business, or in
which the cause of action arose; or if the defendant is a corporation,
of a county in which it may be served or in which the cause of action
arose; provided that:

(i) the summons is served upon the defendant within sixty days after
the period of limitation would have expired but for this provision; or

(ii) first publication of the summons against the defendant is made
pursuant to an order within sixty days after the period of limitation
would have expired but for this provision and publication is
subsequently completed; or

(iii) the summons is served upon the defendant's executor or
administrator within sixty days after letters are issued, where the
defendant dies within sixty days after the period of limitation would
have expired but for this provision and before the summons is served
upon the defendant or publication is completed.

6. in an action to be commenced in a court not of record, the summons
is delivered for service upon the defendant to any officer authorized to
serve it in a county, city or town in which the defendant resides, is
employed or is doing business, or if none of the foregoing be known to
the plaintiff after reasonable inquiry, then in a county, city or town
in which defendant is known to have last resided, been employed or been
engaged in business, or, where the defendant is a corporation, in a
county, city or town in which it may be served, if the summons is served
upon the defendant within sixty days after the period of limitation
would have expired but for this provision; or, where the defendant dies
within sixty days after the period of limitation would have expired but
for this provision and before the summons is served upon the defendant,
if the summons is served upon his executor or administrator within sixty
days after letters are issued.

(c) Claim in complaint where action commenced by filing. In an action
which is commenced by filing, a claim asserted in the complaint is
interposed against the defendant or a co-defendant united in interest
with such defendant when the action is commenced.

(d) Defense or counterclaim. A defense or counterclaim is interposed
when a pleading containing it is served. A defense or counterclaim is
not barred if it was not barred at the time the claims asserted in the
complaint were interposed, except that if the defense or counterclaim
arose from the transactions, occurrences, or series of transactions or
occurrences, upon which a claim asserted in the complaint depends, it is
not barred to the extent of the demand in the complaint notwithstanding
that it was barred at the time the claims asserted in the complaint were
interposed.

(e) Effect upon defense or counterclaim of termination of action
because of death or by dismissal or voluntary discontinuance. Where a
defendant has served an answer containing a defense or counterclaim and
the action is terminated because of the plaintiff's death or by
dismissal or voluntary discontinuance, the time which elapsed between
the commencement and termination of the action is not a part of the time
within which an action must be commenced to recover upon the claim in
the defense or counterclaim or the time within which the defense or
counterclaim may be interposed in another action brought by the
plaintiff or his successor in interest.

(f) Claim in amended pleading. A claim asserted in an amended pleading
is deemed to have been interposed at the time the claims in the original
pleading were interposed, unless the original pleading does not give
notice of the transactions, occurrences, or series of transactions or
occurrences, to be proved pursuant to the amended pleading.

(g) 1. Time computed from actual or imputed discovery of facts. Except
as provided in article two of the uniform commercial code or in section
two hundred fourteen-a of this chapter, where the time within which an
action must be commenced is computed from the time when facts were
discovered or from the time when facts could with reasonable diligence
have been discovered, or from either of such times, the action must be
commenced within two years after such actual or imputed discovery or
within the period otherwise provided, computed from the time the cause
of action accrued, whichever is longer.

2. Notwithstanding paragraph one of this subdivision, in an action or
claim for medical, dental or podiatric malpractice, where the action or
claim is based upon the alleged negligent failure to diagnose cancer or
a malignant tumor, whether by act or omission, for the purposes of
sections fifty-e and fifty-i of the general municipal law, section ten
of the court of claims act, and the provisions of any other law
pertaining to the commencement of an action or special proceeding, or to
the serving of a notice of claim as a condition precedent to
commencement of an action or special proceeding within a specified time
period, the time in which to commence an action or special proceeding or
to serve a notice of claim shall not begin to run until the later of
either (i) when the person knows or reasonably should have known of such
alleged negligent act or omission and knows or reasonably should have
known that such alleged negligent act or omission has caused injury,
provided, that such action shall be commenced no later than seven years
from such alleged negligent act or omission, or (ii) the date of the
last treatment where there is continuous treatment for such injury,
illness or condition.

(h) Claim and action upon certain instruments. Once a cause of action
upon an instrument described in subdivision four of section two hundred
thirteen of this article has accrued, no party may, in form or effect,
unilaterally waive, postpone, cancel, toll, revive, or reset the accrual
thereof, or otherwise purport to effect a unilateral extension of the
limitations period prescribed by law to commence an action and to
interpose the claim, unless expressly prescribed by statute.