In the first of two experiments, responses of two pigeons were maintained by multiple variable‐interval, variable‐ratio schedules of food reinforcement. Concurrent punishment was introduced, which consisted of a brief electric shock after each tenth response. The initial punishment intensities had no lasting effect upon responding. Then, as shock intensity increased, variable‐ratio response rates were suppressed more quickly than variable‐interval response rates. When shock intensity decreased, variable‐interval responding recovered more quickly, but the rates under both schedules eventually returned to their prepunishment levels. In the second experiment, the following conditions were studied in three additional pigeons: (1) With each shock intensity in effect for a number of sessions, punishment shock intensity was gradually increased and decreased and responding was maintained by multiple variable‐ratio, fixed‐ratio schedules of food reinforcement; (2) Changes in punishment shock intensity as described above with responding maintained by either a variable‐ratio or a fixed‐ratio schedule, which were presented on alternate days; (3) Session‐to‐session changes in shock intensity with responding maintained by multiple variable‐ratio, fixed‐ratio schedules. Responding under the two schedules was suppressed to approximately the same extent by a particular shock intensity. Also, post‐reinforcement pauses under the fixed‐ratio schedule increased as response suppression increased.