The Swedish pharmaceutical industry is going through structural changes due to the increased cost of drug development. This has led pharmaceutical firms to outsource clinical trials to Clinical Research Organisations (CRO). This thesis explores the inter-firm relationships between pharmaceutical firms and CROs in the Stockholm area, with focus on the development of trust and commitment. The empirical material gathered from nine qualitative interviews with representatives from both parties suggests that trust and commitment are both important factors. Trust is based on competence and reputation whilst commitment is developed through communication. Commitment is highly valued by the companies that wished to develop long-term relationships. The results also point to challenges in the area mainly regarding patient recruitment that due to the high competition amongst the CROs can lead to opportunism when they are overly optimistic of what they can deliver. This is an issue that needs to be addressed as it affects the whole industry.