sanity testing is done when the build comes from dev team 
to testing tean and smoke testing is done when the build is 
ready to release after adding the release notes and all

but in both the testing we will check whether all mojor 
functionalities are working fine or not

sanity testing is test by the tester and near deployment 
environment.errors are identified related to the operation 
of the stated functions of AUT(application under test)/SUT
(system or software under test). eg:- working of tool 
bar,menu bar in MS word.

smoke testing is development environment. errors are 
identified related to the availability of the stated 
functionality of AUT/SUT.
eg:- Availability of tool bar status bar in MS word.

hello laxmi,

    some persons told smoke testing is done by testers,
is it correct? what is release note? plz give me answer?

smoke testing is a testing which used to test the major 
functionalities of the application. It is also called as 
confidence test or build verification test. If smoke test 
fails, we can ignore to do the further testings means we 
can stop the testing thereitself.
sanity testing is a subset of regression testing. checking 
the functionalities in a depth-wise.
Eg: if u buy a mobile, we will check the major 
functionalities like receiving calls, sending calls, 
receiving msgs and sending msgs.This is all nothing but 
smoke testing.If you do have problem with incoming or 
outgoing calls or msgs, then that mob is unfit to buy. So 
it falls in smoke testing.
After we got mobile, when we have time, we used to go 
through all mobile applications like alarm, ringtones, 
settings, filemanager, entertainment, walkman....This is 
also major functionalies but extra features not consider as 
smoke.This is all nothing but sanity testing.

Sanity Testing is the testing whether the applications is 
ready to test or not.

Smoke testing is the testing the main functionality of the 
application whether there is no time to test in depth