The paper marks the 70th anniversary of the publication of Kalecki’s “The problem of financing economic development” (1955) based on the lectures presented in Mexico City in August 1953. The analysis of the paper is set in the context of Kalecki’s macro-economic analysis of industrialised capitalist economies and of his work at the United Nations. The central messages of Kalecki’s paper are discussed in two parts. The first is focused on what may be termed the real constraints for development and investment, with the political and social obstacles to addressing those constraints. The second is on the funding of balance of payments issues which arise with the problems which methods of funding raise.