I have a home daycare and yesterday, my kids were awful. They were so whiny and screamed as their parents left. It is hard when their routine gets off schedule. Also, at this age, he probably saw another child try this or if you even blinked at his tantrum, he has decided that this behavior works. Did his behavior get you to hold him one more time, to cuddle him, to tell him you are sorry, you will be back, etc. Did the teachers scoop him up and give him extra attention? If so, it worked, he may have genuinely been upset that he had to part with you and preferred to be at home with you, but if he even got an inkling that if he threw a huge fit, it would get you to stay a little longer, than he is going to get worse and louder and scream longer until he determines that no matter how much he gets upset, you are still going to drop him off and leave and come back later just like you did when he was happy. Chances are if you ask his teachers, he is done screaming within one minute from the time you leave. He will get past this and the best thing you can do for him is to kiss him, say goodbye and leave, don't come back, don't let him catch you peeking at him. He will not cry all day and the longer he does cry, it is because he believes you will give in and come back, which will cause the poor little guy to scream for hours when you don't come back like you may have before. I work in the church nursery and it is so frustrating to see parents linger for half an hour while their child cries, leave fore ten minutes, come back for 20 minutes, try to sneak out again, etc. The child jsut is miserable and when they finally just drop them off and go, their kids are happy and secure, knowing they don't have control over their parents behavior allows them to let it go and just accept their situation and have fun. Be strong, he will be ok, and he will be happier in the long run. Whatever you do, DON'T try to sneak off when he is distracted, this will make him more clingy the next time, for he will always be worrying about you leaving or disappearing. It will also reinforce that he needs you to be safe and happy there. Always say goodbye, do a routine like hand the caretakers his bag, kiss and hug him, say goodbye and leave, he will appreciate the security of the routine.