Oral route is technique which is used over a decades. It is most preferred and common technique for oral administration of drug in the body, but due to certain limitation such as absorption of drug, drug targeting to particular organ can cause problem for administration through oral route. To overcome these types of problem as well as for improvement of drug safety and efficiency a novel approach is developed for delivery of drug i.e. In-situ Nasal Drug Delivery System. In-situ gel is a process in which sol form before administration in the body, but once administrated, it undergo gelation in-situ, to form gel. Nasal drug delivery is one of alternative viable route of drug delivery is one of alternative and viable route of drug delivery. Nasal route is rich in vasculature and highly permeable. Nasal route is suitable for those drugs whose oral administration is problematic due to gastric irritation. The present review focused on anatomy of nasal system and criteria required of drug candidate to prepare a gel i.e. In-situ gel. Approaches towards various formulation of in-situ gel with respect to temperature, ph and physiochemical condition.The main role of polymers like Poloxamer, Pectine, Cellulose etc in body, absorption of drug by various methods. Various evaluation parameters which is consider during preparation of in-situ gel.