Background <p>Peritoneal dialysis (PD)-associated peritonitis is one of the main reasons for withdrawal from PD and is associated with worse outcomes. Japan has one of the lowest rates of PD-associated peritonitis in the world, and one of the main reasons for this is thought to be widespread use of device connection systems. However, the benefits of these devices in reducing the incidence of PD-associated peritonitis have not been elucidated.</p> Methods <p>We retrospectively reviewed the medical records of 180 patients treated at Jikei University Hospital and Katsushika Medical Center, in Tokyo, Japan for 257 episodes of PD-associated peritonitis between January 2016 and December 2022. For each patient, we recorded the type of connection, the presence of PD-associated peritonitis infection, the causative bacteria, and the outcome. We investigated between-group differences according to connection method. </p> Results <p>There were no significant differences in the rate of peritonitis (<i>p</i> = 0.29) or exogenous PD-associated peritonitis (<i>p</i> = 0.34) between patients with manual connections and those with device connections. In the analysis of each causative pathogen, peritonitis caused by <i>Staphylococcus aureus</i> was significantly more prevalent in those with manual connections (<i>p</i> = 0.01). Peritonitis caused by aquatic environmental bacteria was observed with device connections. Age at PD initiation (<i>p</i> = 0.049), sex (<i>p</i> &lt; 0.01), and serum albumin levels (<i>p</i> &lt; 0.01) were independently associated with the device connection choice.</p> Conclusion <p>While device connections were often applied to vulnerable patients, no differences in peritonitis rates were observed between device connections and manual connections.</p>