OBJECTIVE: To evaluate the effects of the proximal-terminal colostomy on the healing of colonic anastomosis in rats. METHODS: 36 rats were allocated into two groups: control group (C) with 12 rats subjected to colonic ressectinon and primary anastomosis; colostomy group (CZ) with 24 rats subjected to the same procedure done in the group C, but complemented with a proximal-terminal colostomy. Anastomosis healing was evaluated at the 2nd and 7th post-operative days (PO) by the presence of anastomotic dehiscence and mucosal line, adhesions, bursting pressure, and histologic examination. RESULTS: There was no anastomotic dehiscence in the two groups. Adhesions were more intense in group C at the 7th PO. At both groups, the intestinal rupture was always on the anastomotic line at the 2nd PO; at the 7th PO, most of ruptures happened on the colonic zone out of the anastomotic line (100% of group C and 70% of group CZ). No significant difference was noticied in the other healing anastomotic variables. CONCLUSION: There is no difference in the healing of colonic anastomosis related to the presence or abscence of a proximal colostomy in rats.