Study Objective The current recommended treatment of endometriomata is surgical excision. Our study is assessing recurrence rates of endometrioma following plasma energy ablation treatment. Design 64 endometriomata were treated in 49 consecutive patients identified retrospectively from theatre records of a single operating surgeon, from January 2013 to December 2017. Electronic hospital records were used for data collection and to search for re-attendance for imaging or gynecology review within the whole health board. The maximum time from treatment to clinical review was 66 months. All Patients included in study were treated using plasma energy device, PlasmaJet. Setting University Hospital. Patients or Participants Forty-nine consecutive patients, identified retrospectively. Interventions Endometriomata ablation using plasma energy device. Measurements and Main Results Mean age at surgery was 35 year (+/- 5.8) with a recorded BMI of 26 (+/- 3.8). Median recurrence of symptoms of pain was 20 months. Symptomatic recurrence of endometriomata diagnosed within the health board was 6.2% when looking at total number of cysts treated, with an average time of 19 months from treatment to recurrence. Bilateral endometriomata predicted recurrence compared to unilateral disease with an OR 3.02, RR2.6. Women under the age of 35 years were more likely to be diagnosed with recurrence of endometriomata than women over 35 years with an OR 3.3, RR2.83. Secondary outcomes recorded were recurrence of pain, dysmenorrhoea and peri-operative complications. Conclusion Recurrence of endometrioma in our study is comparable with published rate of recurrence after excision treatment (14-17%). Plasma energy ablation may have lower recurrence rates than other ablation techniques. Formal studies with long term follow up are required.