The present study analizes the mortality of gastric and colon cancer in Spain from 1975 to 1985, and examines the figures obtained for each Spanish province as well as in several major cities. During the study period, proportional mortality for all cancers increased, except for gastric cancer which decreased both for men and women. We found that Soria the highest mean mortality rate due to gastric cancer (81.83), whereas figures were highest for men in Segovia (97.71) and for women in Soria (66.69). By contrast, Gran Canaria had the lowest mean mortality rate due to gastric cancer (6.26), whereas lowest values were obtained for men in Tenerife (8.42) and for women in Gran Canaria (4.11). On the other hand, the highest mortality rate due to colon cancer was found in Gerona (19.11), and the sex distribution was as follows: for men the rate was highest in Gerona (22.22), and for women in Burgos (19.75). Albacete had the lowest mortality Tate due to colon cancer (1.09); for men the lowest was obtained in Avila (1.20), and for women in Albacete (0.90). This geographical distribution suggest that environmental as well as dietary factors may play a role in cancer mortality.