This report covers surveys of radio sources, basic measurements of source parameters and new developments in radio telescopes, instrumental techniques and data processing. The period covered is approximately late 1978 to about August 1981. The results and conclusions of astronomical investigations based on measurements made through the radio window are included in the reports of other commissions, as relevant. Following the practice adopted in 1979, a circular was sent to the Presidents of 18 IAU Commissions and to all members of Commission 40 describing the proposed format of the present report and also identifying contact persons who could be consulted to avoid duplication and to ensure that radio astronomical results are adequately covered by various commissions. I am grateful to all concerned for providing the necessary coordination.