We have performed a study of the influence of the environment on the rate of star formation (SFR) in a sample of galaxies in nearby compact groups. The sample has been chosen from the Catalog of Hickson Compact Groups of Galaxies. High‐quality Hα images of the sample of galaxies in 16 compact groups were obtained and combined with additional deep broadband observations. Comparison of the Hα luminosities relative to the B luminosities of the galaxies in our sample with those of a sample of field galaxies leads us to the conclusion that the environment has different effects on the SFR of the galaxies in groups. Some of the spirals in the groups show depleted SFRs as compared to the field spirals. This result is compatible with the low level of H i emission found for spirals in compact groups by different authors. We interpret this fact to be a result of the stripping of the external gas halos of the spirals as they move across the potential well of the system. Only the disk galaxies of the groups that are experiencing close interactions show enhanced SFRs. The ellipticals and lenticulars in the sample of compact groups show enhanced Hα fluxes compared to field galaxies of the same morphological type. This result has been interpreted as a consequence of the accretion of material from nearby companions. The total Hα emission per unit B luminosity for each group in our sample was compared to the corresponding value computed from models of all possible “synthetic groups” (i.e., built with field galaxies in the same number and morphological composition as the compact groups). Only those groups in which a close interaction is taking place show a significant enhancement of Hα luminosities relative to their corresponding synthetic groups (see Fig. 1). In addition, no significant correlation has been found between the Hα luminosity and relevant dynamical parameters of the groups such as velocity dispersion, mass‐to‐luminosity relation, crossing time, and radius. Figure thumbnail(26 KB) Fig. 1.— Comparison of the ratio of Hα over B luminosities of the groups in our sample with the average values for the synthetic groups. Open squares indicate the measured values for our sample; open triangles indicate the average values for the synthetic groups. Vertical error bars correspond to one standard deviation. Open New Window The H ii region population of a subsample of late‐type galaxies in compact groups was studied. No relationship was found between the slope of the luminosity functions and the morphological types of the galaxies. Also, half of the galaxies of the sample showed a luminosity function fitted by two different slopes. Finally, detailed studies have been performed of two groups of our sample, HCG 31 and HCG 95, which show quite peculiar morphologies and a clear enhancement in the SFR. They show strong interactions between some of their members: HCG 31 contains a merging pair of spirals and abundant recent star formation mostly concentrated in the nuclei of the parent galaxies, but also along the tidal tails developed in the interaction. HCG 95 contains a good candidate for an ongoing merger of three galaxies, as suggested by the number and disposition of the tidal features. In this group, we have shown evidence of transfer of gas from one of the tidal features of the merger toward the elliptical galaxy.