Approximately 5%-7% of patients who have had Achilles tendon rupture (ATR) suffer from contralateral ATR. However, no studies have evaluated the clinical outcomes of contralateral ATR in patients with an existing ATR. Therefore, in this study, we aimed to investigate patient-reported ankle function and activity levels in patients with nonconcurrent bilateral ATR. We retrospectively reviewed the data of 222 patients with an acute ATR who presented at our 2 institutions between 2005 and 2017. All patients had a minimum 2-year follow-up period, with no other major injuries to the ankle joint. Of these patients, 17 patients had nonconcurrent bilateral ATR. Patient-reported outcomes were assessed by telephone interview, using the Achilles tendon Total Rupture Score (ATRS), the ankle activity score, and a patient satisfaction questionnaire. Telephonic interviews were conducted by 2 authors, using a prepared script to minimize bias owing to individual interviewers. The mean age of the patients was 45.1 ± 9.8 years, and 89% were men. Patients with nonconcurrent bilateral ATR had significantly lower values in terms of ATRS, ankle activity score, and satisfaction with current activity level, compared to patients who had unilateral ATR (p < 0.001, p = 0.027, and p = 0.012, respectively). Patients with nonconcurrent bilateral ATR had poorer ankle function, activity levels, and satisfaction than those with unilateral ATR in terms of patient-reported outcome measures with an intermediate-term result and a 2-year minimum follow-up period. These results emphasize the importance of the impact of contralateral injury on the prognosis of patients with ATR and the need for efforts to prevent contralateral rupture.