Maran,
It would have been helpful to include an example, so any response could
be a bit more specific.
You'll want to use the value of some field on the form as a criteria
against that same field in your combobox query.
For example... field [City] = "Boston" on a form.
In the query behind the combo, against the City field, a criteria of...
=Forms!frmYourFormName!City
will filter the records returned in the combo to only "Boston" in the City
field.
--
hth
Al Campagna
Microsoft Access MVP
http://home.comcast.net/~cccsolutions/index.html
"Find a job that you love... and you'll never work a day in your life."
Maran said:
I want a combo box (which is placed in the sub form) to display only those
rows, which falls under the creiteria given in the main form