I am babysitting a 13 month old this week and my 17 month old is jealous! He is around other kids at church and he plays with his cousins, and does fine then, but I don't know if it's because now another baby is in our house playing with his toys, or what. He has hit the baby twice and I have spanked his leg, told him no, and put him in his bed for a minute, and then he did better. But then the next day he starts it again. He gets upset when the other baby plays with his toys. Has anyone here ever dealt with this?

Ah the memories!

Your son is acting out because he feels threatened by this 'intruder into his domain'!
Perhaps, if you suggest that someday, not today, but some day, that baby will be able to do the things that 'big boys' like he can do.
You might say, oh let (your son's name) help you. He knows how to do that. Oh, little one, you can't have that until you are as old as ---.
Ask him what should we do with the so and so today? Sometimes just a touch of your hand on his head or back or arm in passing will reassure him.
When the child leaves tell him what a good helper he is and get a special treat to celebrate!
Good luck!

You son is acting out since their is a new child at his house, playing with is toys etc. I am dealing with this situation at my house as well with my two sons.

maybe he is trying to get attention. maybe he is trying to tell the other child that this is his house and these r his toys. i went through the same thing with my cousins. he'll grow out of it soon. he just needs to no that sooner or later there will be other people using his stuff and he needs to just get over it. sharing is caring. you can tell him that if he wants him and the other little one can both share and play together. k?

Thanks for the advice! I am only keeping this baby this week, but it is some good advice for later on, too, when hopefully he has a little brother or sister (we're hoping for one to be on the way very soon!) I like Nonny's advice about trying to make him feel like a big boy, because he is trying to become Mr. Independent these days anyway!