Saha stood as a candidate for North-West Calcutta in the 1951 Lok Sabha election. He ran as a member of the Union of Socialists and Progressives, but maintained his independence from the party. His goal was to improve the planning of education, industrialisation, healthcare, and river valley development. He was up against Prabhu Dayal Himatsingka. Due to low funding for his campaign, Saha wrote to the publisher of his textbook Treatise on Heat to ask for an advance of ₹5000. He was elected by a margin of 16%.