A research on the macroinvertebrate community was made in the Paloblanco gulch, located in the Otun River basin, (Risaralda, Colombia). Two sample points were selected, the headwaters and the mouth’s closer zone in the Otun River and both presented first order river geomorphology characteristics. The functional units (litter, stone, moss and gravel) were collected and conjunctly with derive and general fauna samples (not including discrimination in the functional units) were taken at each point. 42 Insecta families were founded, also Acari, Annelida, Crustacea and Hirudinea .