Is Employee contribution mandatory for EPF?

Yes, it is mandatory. 

Dear sir,
I am working an institute ( autonomous body) last five years but they not give me epf no. They not dedudcted amount for epf or they not give me epf account.there are all employees is contractual but some employes have epf but i not have epf no. Where i complaint this . this is compulsury for epf.
Thank you

First, you check with your employer about this issue. If you get satisfactory answer then leave it. Otherwise, raise the issue with EPFO Grievance Cell Online.