aims: to determine the rate of colorectal cancer (crc) screening in general practice and to analyse social and demographic factors associated with screening. study type: descriptive. setting: unidade de saúde familiar (usf) horizonte and centro de saúde (cs) de vila do conde/modivas. population: patients aged 50 to 74 years old in 2006, registered with a family physician in usf horizonte and cs de vila do conde/modivas methods: a random sample of 504 people was selected. age, sex, educational level, number of chronic diseases and data on completion of screening tests were collected from patient records. chi-square test, t-student test and logistic regression analysis were performed (p = 0,05). results: the sample had a mean age of 60 years and 57.3% of the patients were women. the screening rate for crc was 24.6%. there was a statistically significant association found between the number of chronic diseases and performance of screening. age was associated with screening. however, when adjusted for other variables, this relationship was not found to be significant. conclusions: the screening rate for crc was similar to that found in other international studies. gender, age and educational level were not associated with screening. the presence of chronic diseases may lead to more medical consultations, which can provide more opportunities for screening. the low rate of screening found requires further study to determine other variables that may affect the performance of screening.