>I want to try to find out of a parameter can accept nulls. The syscolumns has an IsNullable column, but it's always 1. Know of any way to determine if a parameter for a proc can accept a null value?

I suspect there is no simple way to determine if the parameter can accept NULL or not. I believe by default all parameters are NULL or usually I put

@MyParam = NULL,
...

in parameters definition.

Just in case I asked your question on another board.