Timetabling problem is basically an optimisation problem and is a subset of scheduling problems. A timetabling problem is a problem where events (classes, examination and student) have to be ordered in time slots while satisfying some basic constraints. Here the basic aim is to satisfy various constraints, such as, no student can be scheduled for more than one course at the same time and the maximum number of students that can be scheduled to any particular class must not exceed the sitting capacity of the class. So, the timetabling problem is basically arranging the given set of values (class, subject and students) in such a manner such that the resulting schedule should fulfil all the above stated hard constraints and try to give more close values near to the soft constraints (such as proper distribution of classes over available slots). In the present work, examination timetable and class timetable problems have been considered with several practical features. The problems are formulated as mathematical models and heuristic approach is also proposed to solve them. The heuristic uses the basic framework of genetic algorithm.