The plot of Welcome begins with the introduction of three characters Uday Shetty (Nana Patekar), Majnu (Anil Kapoor) and Sikander (Feroz Khan). The threesome are members of a criminal syndicate based in Hong Kong. Dr. Ghungroo (Paresh Rawal), a respected man in the society is on the look out for a bride from a civilized and revered family for his nephew Rajiv (Akshay Kumar). On the other hand gangsters Majnoobhai (Anil Kapoor) and Uday Shetty (Nana Patekar) are in search of a polite, well educated and respectable husband for their sister Sanjana (Katrina Kaif).
Uday Shetty accidentally bumps into Rajiv and gets convinced that he would be the perfect match for his sister. Majnoobhai and Uday are on the peak of happiness having found the perfect match for their sister. Only till uncle Ghungroo finds out about their background and refuses to agree.
Meanwhile, unaware of all that is happening back home Rajiv and Sanjana meet on a cruise and the couple instantly fall for each other. Dr Ghungroo accepts Sanjana into the family, not knowing that she is Uday’s sister. But he soon realizes his blunder and refuses to agree for the wedding.