Background The World Health Organisation estimates a global deficit of approximately 4.3 million health workers, particularly doctors, nurses and midwives. Guinea-Bissau is among the 36 countries that suffer from a critical need for human resources (less than 23 health professionals per 10.000 inhabitants). The present research investigates the impact of clinical trials on health worker’s capacity and training.

Methods This is a qualitative study. I interviewed health professionals who assisted in clinical trials during the past five years and obtained assistance to attend health-related courses. The interviews collected data about the professional’s technical capacity, clinical practices, work conditions, their qualification for their work and socio-economic variables. Additionally, documents about clinical trials conducted in Guinea-Bissau through North-South cooperation, were analysed.

Results Interviews were held with 35 health professionals (21 female, 14 male) who participated in clinical trials with the Bandim Health Project (Guinea-Bissau) as research assistants and who received subsidies to realise undergraduate or graduate degrees. Among those interviewed, 28 (80%) received support to realise an undergraduate degree in nursing, 4 (11%) a laboratory course, and 3 (9%) a postgraduate course. Twenty-four (24; 69%) stated that they experienced significant improvements in their working conditions within the institutions where they worked after their clinical trials; 7 (20%) declared that they have progressed in their career after being placed in a health center or a hospital; 29 (83%) stated that the participation in clinical trials significantly strengthened their technical capacity and had a positive impact on their careers.

Conclusion I observed a positive impact of the involvement in clinical research on the development of health professionals’ capacity. However, the quantity of clinical research in Guinea-Bissau is insufficient to train all health practitioners in this area.