How can I get custody of my nieces and nephews

The department of social service took my sister in laws kids, what can I do to get custody of them?

I'm not a legal expert but I can tell you right now, they're going to need more info then that.

For instance, why would you want custody, why shouldn't they remain with their parents?

Are they in their parents custody at this time?

How old are they?

You get the picture. :)

the department of social service took my sister in laws kids, what can i do to get custody of them?

Contact the department and ask, is the first thing I would do.