Purpose To identify the extent of persistence (period of time of continuous therapy with the drug prescribed) of glaucoma patients treated with prostaglandins (latanoprost, bimatoprost, or travoprost), or β-blocker (timolol) monotherapy. Methods An observational retrospective study of a 24-month follow-up in 191 patients (from four centers) was done to identify the time elapsed until patients discontinued their antiglaucomatous treatment. The relevant information was extracted from patients’ medical charts. A descriptive analysis, a Kaplan–Meier survival analysis, and a Cox regression model were used to determine which drug was associated with greater patient persistence and to detect variables significantly influencing persistence. Results Descriptive analysis and survival curves showed that after 24 months, latanoprost was associated with a higher persistence in glaucoma treatment than the alternative agents: 81.6% versus 22.9% for bimatoprost, 65.4% for travoprost, and 60.5% for timolol (P < 0.0001). Persistence was significantly influenced by the antiglaucoma agent used as monotherapy (with a six-fold higher risk of treatment discontinuation during the follow-up period due to receiving bimatoprost instead of latanoprost; P < 0.0001) and patient age (P = 0.001). Even though comorbidities could not be directly related to persistence, their occurrence was related to patient age. The main reasons for treatment discontinuation were lack of efficacy, development of intolerance and/or adverse events, which were significant in the bimatoprost group, 28.6% (P < 0.001) and 48.6% (P < 0.001), respectively. Conclusions Latanoprost shows higher patient persistence compared with travoprost, bimatoprost, and timolol in routine clinical practice, and could lead to better control of intraocular pressure and lower associated economic costs.