BACKGROUND: There is growing evidence that pharmacists' interventions to solve drug-related problems are effective and cost-saving. Since 1978, under the Québec provincial drug plan, payment for two cognitive services, the pharmaceutical opinion and the refusal to dispense a prescription, has been disbursed to community pharmacists. However, the number of claims for these services lags far behind expectations. OBJECTIVE: To identify factors influencing Québec community pharmacists in the billing for a pharmaceutical opinion or for a refusal to dispense. METHODS: Questions on predisposing, enabling, and reinforcing factors potentially related to pharmacists' behavior were included in a self-administered questionnaire sent to all 3517 community pharmacists practicing in the province of Québec during 1996. Using multivariate logistic regression, models were built to explain billing for an opinion and billing for a refusal. RESULTS: According to our models, the typical pharmacist who billed for opinions or refusals in Québec is <45 years of age, has attended a continuing education program on this topic, and believes that billing for interventions is important. This typical pharmacist handles a mean daily volume of 100–250 prescriptions, uses a decision-support computer program, and has sufficient technical staff assistance. This pharmacist believes that interventions can be billed rapidly and are consistently paid by the province's drug plan. CONCLUSIONS: In order to increase the billing of pharmaceutical care in community pharmacies, tailored educational programs should be offered to pharmacists. There is also a need to improve working conditions in pharmacies.