In this study, we have assessed whether referral for primary radiotherapy varied according to hospital size in a region with 1 million inhabitants served by community hospitals. We studied 20178 patients diagnosed with breast, non-small cell lung, prostate, rectal, or endometrial cancer between 1988 and 1999. We used logistic regression analysis, adjusted for age, stage and period of diagnosis. Medium-sized and small hospitals referred breast cancer patients more often (OR=2.2, 95%CI: 2.0-2.5, OR=1.2, 95%CI: 1.1-1.4, respectively), and patients with prostate cancer less often (OR=0.7 (0.5-0.8) and 0.7 (0.6-0.9), respectively). Referral rates for patients with non-small cell lung and rectal cancer showed minor differences according to hospital size, referral for endometrial cancer was somewhat higher for patients from medium-sized hospitals (OR=1.5 (1.0-2.1)). Time trends in variation were shown, but differences according to hospital size only decreased over time for rectal cancer. Despite multidisciplinary oncology meetings and treatment guidelines there were large variations in rates of referral for radiotherapy.