Purpose To evaluate the safety and efficacy of intravitreal administration of a steroid and antibiotics during cataract surgery compared with the typical postoperative topical regimen in preventing postoperative inflammation, pain, cystoid macular edema (CME), and endophthalmitis. Setting Private practice, Sioux Falls, South Dakota, USA. Design Retrospective case series. Methods The study group included eyes that had an intravitreal injection of triamcinolone–moxifloxacin–vancomycin at the time of cataract surgery with concomitant trabecular microbypass stent insertion. The control eyes had the same procedure but were prescribed topical antibiotics, steroids, and nonsteroidal antiinflammatory drugs postoperatively. Data were recorded preoperatively and 1 day, 1 week, 1 month, and 3 months postoperatively. Primary outcomes included the number of glaucoma medications, intraocular pressure (IOP), and IOP spikes of at least 15 mm Hg from baseline. Results There were 234 eyes in the study group and 249 eyes in the control group. The mean reduction in glaucoma medications was 0.24 drops in the study group and 0.80 drops in the control group 3 months postoperatively, whereas the mean IOP reduction was 2.59 mm Hg in the study group and 3.63 mm Hg in the control group. Pressure spikes were detected at 54 (5.7%) of 936 postoperative visits in the study group and at 37 (3.7%) of 996 visits in the control group. There were no cases of severe inflammation, CME, infection, or retinal detachments. Conclusions Both groups had similar postoperative pressure reductions and incidence of IOP spikes. The results indicate that intravitreal injections of a steroid and antibiotics might be a safe option for glaucomatous eyes having cataract surgery with trabecular microbypass stent insertion.