Despite the availability of effective medication, blood pressure control rates are low, particularly in low‐ and middle‐income countries. Adherence to medication and follow‐up visits are important factors in blood pressure control. This study assessed the effectiveness of reminder telephone calls on follow‐up visits and blood pressure control among hypertensive patients as part of the Mumbai Hypertension Project. This project was initiated by PATH with the support from Resolve to Save Lives from January 2019 to February 2020. The study included hypertensive patients attending 164 private practices in Mumbai, India; practitioners screened all adults visiting their clinic during the project period. Among 13 184 hypertensive patients registered, the mean age was 53 years (SD = 12.38) and 52% were female. Among the 11 544 patients that provided phone numbers and gave consent for follow‐up calls, 9528 responded to phone calls at least once and 5250 patients followed up at least once. Of the 5250 patients, 82% visited the clinic for follow‐up visit within one month after receiving the phone call. The blood pressure control rate among those who answered phone calls and who did not answer phone calls increased from 23.6% to 48.8% (P <.001) and 21.0% to 44.3% (P <.001), respectively. The blood pressure control rate at follow‐up was significantly associated with phone calls (OR: 1.51, 95% CI: 1.34 ‐ 1.71). The study demonstrates that telephone call intervention and follow‐up visits can improve patient retention in care and, subsequently, blood pressure control among hypertensive patients attending urban private sector clinics in India.