In a study of 445 patients with colorectal cancer referred to our center during a 3-yr period, we investigated the following parameters and their interrelationships: sex, marital status, ethnic origin, place of residence, stage of disease, delay in diagnosis and factors responsible for delay. Localized disease was found in 52% of the patients, regional disease in 29% and metastatic disease in 19%. The incidence of colorectal cancer was significantly higher in Jews of European (occidental) descent than in Jews of Asian or North African (oriental) descent or in Arabs. The median and mean ages were significantly higher in the occidental than in the oriental Jewish group and significantly lower in the Arabs than in the oriental Jews. Diagnosis was delayed for more than 6 weeks in 52% of the patients. Responsibility for the delay could be attributed to the patient in 54% of these cases and to the physician in 47%. Administrative factors were responsible for the delay in 26%. (In 27% of the above delayers there was more than one agent responsible for the delay.) On average, patients in whom diagnosis was delayed had more advanced disease than those without delay. Also, patients with advanced disease had a longer delay on average than those with localized disease. The stage of disease at diagnosis was more advanced in the oriental than in the occidental Jews. No correlations were found between delay in diagnosis and either age or sex. There were more widowers with delay (21%) than with no delay (16%). In patients living outside Haifa delay was more prolonged than in those residing in the city. Educational programs aimed at the population at risk of developing neoplasm and especially at those likely to undergo delay in diagnosis are recommended. Postgraduate courses should be designed to instruct physicians on how to minimize delay in diagnosis.