>I am working with VFP 3.0
>
>Is it possible in a populated grid to have certains rows (records) read-only?

In the AfterRowColChange of the grid, put your code to make the Grid read only based on whatever condition you need. Also, make sure you turn ReadOnly off if the condition is not met.

if ReadOnlyCondition_Here
   This.ReadOnly = .t.
else
   This.ReadOnly = .f.
endif