Is there any prblm for getting good marks in the GATE if we avoid any subject???...

It depends on how many subject you are leaving and the weight-age on each. eg if you are leaving digital logic, DB , OS each carrry aroung 3-7 marks. while DS, Algo both together carry 15 marks. What I suggest its ok to leave 2-3 subjects if you are final year student / or have limited time. But you must study atleast for 70-80 marks to score 60+ .