In order to investigate the mass-to-light ratio in irregular Magellanic galaxies, a sample of 21 Sdm, Sm, Im objects, for which high-resolution velocity fields observed in 21 cm line are available in the literature, has been selected. Rotation curves, either taken from the authors or reconstructed from the original data and sometimes supplemented with other informations published elsewhere, are shown in Fig. 2. The homogeneous “de Vaucouleurs” distance scale was adopted.