BACKGROUND AND PURPOSE: A survey was conducted of radiotherapy (RT) resources and utilization in a northwestern Italian Region in order to assess geographical variations in radiotherapy utilization rates, and the effects of infrastructure supply on accessibility. MATERIALS AND METHODS: The survey was conducted by analysing standardized utilization rates based on administrative records. The data were analysed at both Regional and Local Health Unit (LHU) level. RESULTS: Wide variation was found among LHUs RT utilization rates--the sex- and age-standardized rates varied from 1.8/1000 inhabitants to more than 3/1000 inhabitants. Patients resident in LHUs with no RT service showed a lower probability of accessing RT (standardized rate ratio (SRR), 0.82; 95%IC, 0.80-0.85). The utilization rate decreased in relation to the distance between a patient's residence and the nearest RT service; the reduction was greater for patients > or =70 years of age. CONCLUSION: The wide geographic variation implies lack of equity in access to services. Utilization levels decreased significantly with increasing distance from the nearest RT service, distance being a barrier to access particularly for older persons. The heterogeneous distribution of services on the Regional territory seems a relevant explanation of differences in utilization rates.