My ex-wife called mid week and said she was going to be evicted and needed me to take the children ages 4 and 3 for a while instead of having them live in a safe house with her. This is her 3rd eviction within a year, and the fourth place she has moved to. She has had 3 jobs within the year and has quite or even been fired for job abandonment. I pay over 600 per month in child support and I feel that she doesn't have her act together enough to take care of the children. What are my chances of getting custody of my children?

Sounds like you have a decent chance since you should be able to prove she is not providing the kids with a stable home environment.

My ex-wife called mid week and said she was going to be evicted and needed me to take the children ages 4 and 3 for a while instead of having them live in a safe house with her. This is her 3rd eviction within a year, and the fourth place she has moved to. She has had 3 jobs within the year and has quite or even been fired for job abandonment. I pay over 600 per month in child support and i feel that she doesn't have her act together enough to take care of the children. What are my chances of getting custody of my children?
Your scenerio sounds almost identical to my step-daughters situation. I too am in Kansas... you have a very good chance, provided you have nothing to hide from the court. As a parent, I couldn't stand knowing my kids were living with so much instability.
If you don't act on taking custody, and someone calls Social Rehabilitation Services on her.. you both could be looking for them in a Foster home... Step up Dad and be their hero! Good luck to you!

I'm looking at a very similar situation myself. My ex is living with her parents but they have kicked her out of the house a few times and she can't/won't hold a job. I pay $600 in support and she blows it on stuff not related to our childrens' needs.

I'm very interested to hear what happens in your case... I'm gearing up to do the same thing as it sounds like you may be (the exact reason I'm on this forum).