Our objective in this study was to create AAPM TG 119 test plans for intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in the Monaco planning system. The results were compared with the published studies, and the performance of the Monaco planning system was analyzed. AAPM TG 119 proposed a set of test cases called multi-target, mock prostate, mock head and neck and C-shape to ascertain the overall accuracy of IMRT planning, measurement, and analysis. We used these test cases to investigate the performance of the Monaco planning system for the complex plans. For these test cases, we created IMRT plans with static multi-leaf collimator (MLC) and dynamic MLC by using 7–9 static beams as explained in TG-119. VMAT plans were also created with a 320° arc length and a single or double arc. The planning objectives and dose were set as described in TG 119. The dose prescriptions for multi-target, mock prostate, mock head and neck, and C-shape were taken as 50, 75.6, 50 and 50 Gy, respectively. All plans were compared with the results of TG 119 and the study done by Mynampati et al. Point dose and fluence measurements were done with a CC13 chamber and ArcCHECK phantom, respectively. Gamma analysis was done for the calculated and measured dose. Using the Monaco planning system, we achieved the goals mentioned in AAPM TG-119, and the plans were comparable to those of other studies. A comparison of point dose and fluence showed good results. From these results, we conclude that the performance of the Monaco planning system is good for complex plans. © 2015, Japanese Society of Radiological Technology and Japan Society of Medical Physics.