Organization of anticoagulation therapy in general practice is described on the basis of data from 56 general practitioners interviewed by questionnaire. The average number of patients controlled by each practitioner was 12.0, and 52% of the general practitioners performed the analyses themselves. In municipalities with a local hospital only 13% of the general practitioners performed the analyses themselves, compared with 75% in municipalities without a hospital. The average weekly number of Thrombotests performed by each practitioner was 12.2. When an external laboratory was used 88% were contacted earlier in the case of International Normalized Ratio (INR) > 4.8 while this was uncommon (12%) in the case of International Normalized Ratio