Surgical site infections (SSIs) are the second most common healthcare-associated infection. Active SSI surveillance can help inform preventative measures and assess the impact of these measures. We aimed to describe the evolution in trends over 14 years of prospective active SSI surveillance and implementations of SSI prevention measures in a French Teaching Hospital. We monitored and included in the study all surgical procedures performed from 2003 to 2016 in eight surgical units. The semi-automated surveillance method consisted of weekly collection of SSI declaration forms (pre-filled with patient and procedure administrative data and microbiology laboratory data), filled-in by surgeons and then monitored by the infection control practitioners. A total of 181,746 procedures were included in our analysis and 3270 SSIs recorded (global SSI rate 1.8%). The SSI rate decreased significantly from 3.0% in 2003 to 1.1% in 2016. This decrease was mainly in superficial SSIs and high infectious risk procedures. Higher SSI rates were observed for procedures associated with the usual risk factors. During this 14-year period, several evolutions in surgical practices occurred that might have contributed to this decrease. With an overall decrease in SSI rate throughout the surveillance, our results revealed the benefits of an active and comprehensive hospital SSI surveillance programme for understanding the SSI rate trends, analysing local risk factors and assessing the effectiveness of prevention strategies. These findings also highlighted the importance of the collaboration between surgeons and infection control practitioners.