OBJECTIVES: To conduct a meta-analysis on the diagnostic accuracy of five screening tests for colorectal cancer (CRC): faecal occult blood test (FOBT), double-contrast barium enema (DCBE), flexible sigmoidoscopy (FSIG), conventional colonoscopy (COL) and computed tomography colonoscopy (CTCOL). METHODS: A literature search was carried out in MEDLINE (1966-2004) for each of the five tests. Articles were reviewed by two independent reviewers according to the Berkeley Systematic Reviews guidelines. Inclusion criteria were: 1) RCTs or observational studies of screening methods for CRC; 2) subjects patients with low to average risk of colorectal cancer; and 3) complete data to calculate sensitivity and specificity. Exclusion criteria were: 1) non-peer reviewed articles; 2) any articles whose primary aim was not to assess colorectal cancer screening; 3) articles not in English or French; 4) articles published prior to 1975; and 5) high risk screening populations. Heterogeneity within screening test groups was evaluated using X2 test. Combining diagnostic accuracy measures, a summary operator-receiver curve (SROC) was constructed with sensitivity (from pooled data) and specificity (from SROC) for each CRC screening test. RESULTS: Initial literature search found 399 for FOBT, 253 for DCBE, 394 for FSIG, 434 for COL, and 345 for CTCOL. Of these, 12, 8, 10, 8, and 13 articles respectively, were selected for inclusion in the final analysis. COL is the only screening strategy without significant heterogeneity among studies (p=0.078). Sensitivity and specificity for FOBT, DCBE, FSIG, COL and CTCOL was 0.543 and 0.976, 0.760 and 0.990, 0.749 and 0.9998, 0.866 and 0.999, 0.867 and 0.972, respectively. CONCLUSIONS: Specificity of all screening tests is high with greater variation evident in the sensitivity (0.54-0.87) estimates. COL results are considered most reliable. Additional studies are required to validate CTCOL results due to significant heterogeneity. Positive FOBT, DCBE, FSIG and CTCOL results must be further investigated with COL.