Our research consisted in analyzing the contribution of Quality in improving performance in the transport sector company in the DRC from 2014 to 2018, the case of Société Commerciale des Transports et des Ports, SCTP, in acronym. The objective pursued by this research was to show the importance of Quality in transport companiesś by highlighting the two strands to be followed: reducing the cost of NON-QUALITY and seeking COMPETITIVENESS. Our concerns centered on two fundamental questions: - Does SCTP SA have a Quality Assurance system? - Does Quality Assurance help to improve commercial, economic and financial performance? - In view of the various questions raised, the following hypotheses were put forward: - Quality Assurance would not exist within SCTP; - Quality Assurance would have a positive impact on economic, financial and commercial performance. To verify these various hypotheses, we used the following methods and techniques: Historical, descriptive and statistical methods. These methods were supported by documentary techniques.