The widespread use of pesticides in Egypt, the high incidence of colorectal cancer in Egyptian children and young adults, and the published U.S. case reports in which pesticides have been connected with colorectal cancer led the authors to investigate the possible association between organochlorines and colorectal cancer. The authors conducted a pilot study to describe serum organochlorine levels among 31 Egyptian colorectal patients and 17 controls. High levels and large interindividual variability of p,p'-dichloro-diphenyldicholoroethylene (DDE), dichloro-diphenyl-trichloroanthane (DDT), beta-hexachlorocyclohexane (beta-HCH), and hexachlorobenzene (HCB) levels were found among most subjects, especially those from rural areas. Farming and aging were each associated positively with high serum organochlorines. Colorectal cancer patients had higher serum organochlorines levels than controls. The high levels of organochlorines reported and their relation to age, residence, occupation, and disease status justify further study of the possible association between organochlorine pesticides and colorectal cancer in a larger population in Egypt.