Also known as Science Block, this building was inaugurated in 2002 by the then Defense Minister of India Sri George Fernandes. Lying at the hind side of A-Block, the Xavier Block is named after St. Francis Xavier, one of the founding members of the Society of Jesus in 1540. The building houses undergraduate science faculties and laboratories – Botany, Zoology, Biotechnology, Biochemistry, Chemistry, Electronics, Mathematics, Statistics and Physics. The top floor houses Laboratory of Applied Biology of international repute in Tissue Culture supervised by Fr Leo D’Souza. The building also has an observatory – Al-Solarium.