Patients with indolent conjunctival lymphomas exhibit good prognosis, with exceptional cases of dissemination, and are suitable candidates for intralesional therapies. We report the first prospective phase 2 trial using intralesional rituximab supplemented with autologous serum in adults with relapsed/refractory indolent CD20+ lymphoma of the conjunctiva (NCT01514344). Patients received 4 weekly intralesional injections of rituximab, followed by 6 monthly injections; 500 μL of autologous serum was added to rituximab in patients with lymphoma unresponsive to weekly doses. Safety, activity, and antitumor effect of autologous serum were investigated. Twenty patients with mucosa-associated lymphoid tissue (MALT)-type lymphoma were enrolled. Tolerability was excellent, with only 3 mild local reactions. After weekly injections, 11 patients achieved tumor regression, 8 had stable disease, and 1 experienced progressive disease; 9 patients received autologous serum, with response improvement in 4 cases (3 complete responses, 1 partial response). At the end of treatment, 12 patients achieved a complete remission, and 1 achieved a partial response, with an overall response rate of 65% (95% confidence interval, 45-85). At a median follow-up of 42 months (range, 10-78), 12 patients remain relapse free, with 5-year progression-free survival and time-to-next-treatment rates of 59% ± 11% and 69% ± 11%, respectively. Three patients with local relapse were retreated with intralesional rituximab and serum; 2 achieved a complete response that lasted 25+ and 38+ months. Thus, intralesional rituximab is a safe and active therapy in patients with relapsed conjunctival MALT lymphoma. The addition of autologous serum improves response in some cases. Retreatment of local relapses can result in a second durable remission.