Two approaches to the recruitment of subjects for screening for fecal occult blood were tested in two middleclass neighborhoods in Jerusalem. After invitations were mailed to 2,909 persons aged 40 and older, 855 (29%) requested the special “Colo-Screen” packet of slides; and 496, one-sixth of those contacted originally, ultimately returned stool specimens for examination. In a parallel campaign by family doctors, invitations were distributed personally to 324 patients visiting a Sick Fund Clinic; 225 (69%) requested Colo-Screen slides and 137 (42% of the persons invited) sent in stool specimens. Males and females responded equally. Of the 633 specimens received, 29 (4.6%) were positive for occult blood; two cancers and seven adenomatous polyps were found and resected. Screening programs for colorectal cancer should encourage greater personal participation of family doctors in the recruitment process.