PURPOSE: The aim was to compare the postsurgical outcomes of trabeculectomy (TET) and transscleral cyclophotocoagulation (CPC) in a similar cohort of eyes diagnosed with primary open-angle glaucoma (POAG). MATERIALS AND METHODS: For this monocentric non-randomized retrospective comparative trial, the records of eyes which underwent TET or CPC between 2013 and 2016 at our institution for the treatment of POAG were reviewed. Parameters analyzed before surgery as well as 1 and 2-3 years afterwards were visual acuity (VA), intraocular pressure (IOP), mean defect (MD) of the visual field, number of glaucoma medications and the objective refraction using which the surgically induced astigmatism (SIA) was calculated. RESULTS: In total, 51 eyes of 51 patients underwent TET and 45 eyes of 45 patients underwent CPC. Mean VA dropped in both groups on the last follow-up after surgery (TET-group: 0.17 ± 0.17 to 0.23 ± 0.28 logMAR, p = 0.01/CPC-group: 0.22 ± 0.22 to 0.26 ± 0.27 logMAR, p = 0.01). In the TET- and CPC-groups IOP decreased significantly (TET: 24.9 ± 6.4 to 14.9 ± 3.1 mmHg, p = 0.001/CPC: 23.0 ± 6.5 to 16.0 ± 4.1 mmHg, p = 0.001) although more pronounced and less depending on IOP-lowering medication in eyes after TET. MD remained stable after TET (7.4 ± 4.8 and 8.1 ± 4.9 dB, p = 0.1) but further deteriorated in eyes after CPC (9.0 ± 4.9 and 10.7 ± 4.6 dB, p < 0.001). SIA was comparable in both groups on the last follow-up (TET: 0.83 ± 0.69 D; CPC: 0.91 ± 0.65 D, p = 0.6). CONCLUSION: The IOP reduction achieved without medication was more pronounced in the TET-group compared with the CPC-group. Visual field remained stable in the TET-group, while further deteriorating in the CPC-group during follow-up. Eyes undergoing CPC had a higher demand for additional medication to reach comparable success rates as TET. Due to this performing TET is favorable over CPC in POAG eyes.