This study aimed to evaluate, in detail, the implementation of the self-management intervention used in the TASMINH2 trial. The intervention, comprising self-monitoring for the first week of each month and an individualised treatment self-titration schedule, was developed from a previous trial of self-management. Two hundred and sixty-three patients with poorly controlled but treated hypertension were randomised to receive this intervention and underwent training over two or three sessions. Participants were followed up for 12 months during which time process data were collected regarding the persistence and fidelity of actual behaviour compared with intervention recommendations. Two hundred and forty-one (92%) patients completed training of whom 188 (72%) self-managed their BP and completed at least 90% of expected self-monitoring measurements for the full year of the study. Overall, 268/483 (55%) of recommended medication changes were implemented. Only 25 (13%) patients had controlled BP throughout the year and so were not recommended any medication changes. Adherence to the protocol reduced over time as the number of potential changes increased. Of those self-managing throughout, 131 (70%) made at least one medication change, with 77 (41%) implementing all their recommended changes. In conclusion, self-management of hypertension was possible in practice with most participants making at least one medication change. Although adherence to the intervention reduced over time, implementation of treatment recommendations appeared better than equivalent trials using physician titration. Future self-management interventions should aim to better support patients' decision making, perhaps through enhanced use of technology.