To compare outcomes of illuminated microcatheter–assisted circumferential trabeculotomy vs combined mitomycin C–augmented trabeculotomy-trabeculectomy for primary congenital glaucoma.Prospective, randomized trial.Of the 30 patients (60 eyes) analyzed with bilateral primary congenital glaucoma aged ≤2 years, 1 eye of each patient was randomized to: illuminated microcatheter–assisted trabeculotomy (Group I) or combined trabeculotomy with trabeculectomy augmented with mitomycin C (Group II). Primary outcome measure was intraocular pressure (IOP) reduction. Categorization into absolute success (IOP ≤15 mm Hg without medication) and qualified success (IOP ≤15 mm Hg with medication) was done. Secondary outcomes included change in corneal diameter and clarity, optic disc status, refraction, need for anti-glaucoma therapy, and occurrence of complications.Mean age of patients was 6.63 ± 5.74 months. IOP fell by 49.3% (22.25 ± 10.88 to 11.56 ± 3.33 mm Hg) in Group I and 46.6% in Group II (21.73 ± 8.89 to 11.60 ± 3.03 mm Hg) (P < .001 in both). At 1 year, absolute success was achieved in 86.7% (26/30) and 90.0% (27/30) in Groups I and II, respectively (P >.99) and qualified success in 93.3% (28/30) in both groups (P = 1). There was significant improvement in corneal clarity (P < .001) and cup-to-disc ratio (P ≤ .01) in both groups at 1 year. Though incidence of hyphema was significantly more in Group I (P = .0001), no vision-threatening complications occurred in either group.Illuminated microcatheter–assisted circumferential trabeculotomy achieved comparable surgical outcomes to mitomycin C–augmented combined trabeculotomy-trabeculectomy and may be recommended as the initial surgical procedure for primary congenital glaucoma.