PURPOSE: To provide a diagnostic algorithm of recurrence and treatment failure after intravitreal bevacizumab (IVB) injection for retinopathy of prematurity type 1 (ROP1) and the stepwise therapeutic approach for both conditions. METHODS: Retrospective chart review of all patients diagnosed with ROP1 initially treated with IVB in 6 tertiary referral centers of Toluca and Mexico City from 2005 to 2017. Treatment failure was defined as persistence or progression of neovascularization, elevation of the ridge, worsening of plus disease, or retinal crunch within the first week after treatment. Recurrence was defined as the new appearance of plus disease, an elevated ridge, or pathological new vessels after an initial regression of ROP following treatment. Therapy was observation, switch of anti-VEGF agent, retinal photocoagulation, vitrectomy, or a combination of two or more, depending on the severity of findings. RESULTS: A total of 672 patients who received intravitreal bevacizumab injection for ROP1 treatment were included. Of these, 2.5% (17 patients) failed to treatment, 6.8% (46 patients) developed a recurrence for ROP, and 5.5% (37 patients) carried a misdiagnosis of recurrence and were diagnosed with other than ROP1 after examination. Based on the severity of findings, patients with recurrence or treatment failure were further treated by observation, repeat anti-VEGF intravitreal injection (bevacizumab or other), laser photocoagulation, vitrectomy, or a combination of these. Based on the treatment results, a therapeutic algorithm was created. CONCLUSIONS: Intravitreal injection of anti-VEGFs for the treatment of ROP warrants close follow-up as some of these patients may have treatment failure or recurrence of the disease. It is crucial to differentiate between them to avoid a misdiagnosis and offer the correct treatment. We propose a novel algorithm for the follow-up and treatment approach of ROP1 following initial treatment with IVB. This algorithm offers a summary of our recommendations based on a large case series of ROP1 patients. It is meant to grow and expand as more clinical evidence becomes available.