OBJECTIVE: To evaluate the measles epidemiological surveillance system, before and during the COVID-19 pandemic in Pernambuco, Brazil. METHODS: This was a descriptive evaluation of the quality (duplicity; completeness; consistency), timeliness and usefulness attributed, classified as excellent ≥ 90.0%, regular ≥ 70.0% and < 90.0%, and poor (< 70.0%). Data from the Notifiable Health Conditions Information System and Laboratory Environment Management System were used, before (03/11/2018-03/10/2020) and during (03/11/2020-03/10/2022) the pandemic. RESULTS: 1,548 suspected measles cases were registered (1,469 before and 79 during the pandemic). In the two periods studied, there were 11 and 1 duplicate records, average completeness in filling out the variables was 99.2% and 95.7%, while average consistency was 96.7% and 97.5%, respectively. Timeliness (receipt of samples, 16.2% and 33.0%. Release of results, 1.3% and 1.3%) and usefulness (43.5% and 24.4%) were poor. CONCLUSION: Quality was classified as excellent in the periods studied, timeliness and usefulness were classified as poor, signaling non-compliance with the purpose of the system. MAIN RESULTS: The quality of data from the measles epidemiological surveillance system in Pernambuco was excellent, while its timeliness and usefulness were poor during both periods. IMPLICATIONS FOR SERVICES: The limited timeliness and, therefore, the low usefulness of the measles epidemiological surveillance system must be discussed in the three government spheres of health service management, with the aim of training the professionals involved, as well as monitoring and evaluating the system. PERSPECTIVES: Systematic monitoring and evaluation generates evidence that supports health service managers and workers in the timely identification of gaps that compromise the full fulfillment of the objectives proposed.