Many clinicians and clinician-scientists have serious concerns that clinical studies (i.e. studies with patients) are less favorably accepted than basic ('bench') projects by funding agencies and by promotion committees of university departments. However, this commonly held view has not been previously verified. To test whether bias exists against clinical studies, we compared the acceptance rate of clinical vs. basic studies dealing with drugs and therapeutics in children, which were submitted to a large scientific meeting. Of 197 abstracts reporting on drug/therapeutic studies, submitted to the Society for Pediatric Research in 1993, there were 133 clinical and 64 basic studies. Fifty-nine (44.3%) of the clinical studies were accepted, significantly less than the basic projects (n = 47 or 73.4%, p < 0.0001). A basic paper was 66% more likely to be accepted (95% CI 50.7-82.6%). This trend was consistent for different groups of drugs/therapeutics, including analgesics, surfactants, corticosteroids, vaccines, hormones, and antiasthmatics. To examine whether the lower rate of acceptance of clinical papers is the result of lower scientific standard, all papers were scored for their quality by raters who were blinded to their acceptance or rejection status. In general, rejected clinical papers scored significantly higher than rejected basic papers (16 +/- 1.8 vs. 14.8 +/- 1.0, p < 0.05). Our study supports the commonly held but previously unproven view that there is a bias against clinical research, in the context of patient-based studies, when compared to basic (bench) research.