Background/aims: Analyzing temporal trends in cancer incidence rates can generate new insights for the significance of geographical and epidemiological variations of the disease. This study evaluated the time trends over a 15-year period in the frequencies of colon and rectum cancers at various subsites by gender and age. Materials and Methods: Data were obtained from a population-based cancer registry in Adana (a Mediterranean city of Turkey). Among the 47.783 microscopically-confirmed cancer cases during the 15-year period (1993 to 2008), 2.749 (5.8%) colorectal cancer cases were analyzed in three separate 5-year time periods. Results: The incidence of right-sided colon cancer was found to be increasing compared to the left-sided colon cancer (p=0.048) over time in total (19.8% in 1993-1997, 24.4% in 1999-2003, and 25.6% in 2004-2008). This proximal shift of cancers demonstrated a significant increase for females (p=0.041), but not for males. The incidence of right-sided colon cancer was found to increase in advanced age groups (over 70) of males and increase in younger age groups (over 50) of females. There was a corresponding continuous decline in the percentage of rectal cancer (not in distal cancers) in both genders. Conclusions: Although the frequency of colorectal cancer cases was found to be lower in our country when compared to Western countries, a similar right-sided colon cancer shift was observed. The apparent shift of colorectal cancer in young female patients may be related to the advances in diagnostic techniques and may indicate possible diagnostic bias for the female gender. These results also emphasize the importance of collecting regular cancer statistics and of closer follow-up to generate basic epidemiological data and to draw attention to this issue in further detailed analytical research studies.