Academic performance conceptualized as the degree of knowledge that the institution recognizes that a student possesses, it is influenced by various factors: personal, social, economic, institutional, and cultural. Among the social factors involved is the family environment, so in order to determine if there is a relationship between academic performance and family function, the present longitudinal analytical study was carried out. 157 first-year medical students were surveyed who, to determine family functionality, were applied to the family Apgar test at two times during the school year: before the first and before the last partial exam; academic performance was operationalized as the final result obtained at the end of the school year: passed or failed. Of the participating students, 102 (65%) obtained good academic performance, and 49 (31%) of the total considered belonged to functional families. Almost half of the participants, 88 (56%) of them considered that their family function did not change over time. Family functionality in the first measurement did not present a significant difference with the results of the second measurement (McNemar Chi-Square 7.686, p = .262), therefore, for the analysis of functionality and academic performance, the result was takenof the second measurement only. No relationship was found between academic performance and family functionality (p = .177), so other studies must be carried out to define the factors that contribute to successful academic performance.El rendimiento académico, conceptualizado como el grado de conocimientos que la institución reconoce que un estudiante posee, está influido por diversos factores: personales, sociales, económicos, institucionales y culturales. Entre los factores sociales implicados, se encuentra el entorno familiar, por lo que con el objetivo de determinar si existe relación entre rendimiento académico y funcionalidad familiar, se realizó el presente estudio analítico longitudinal. Se encuestaron a 157 estudiantes de primer año de Medicina, a quienes, para determinar la funcionalidad familiar, se les aplicó la prueba de Apgar Familiar en dos momentos: antes del primero y antes del último examen parcial; el rendimiento académico se operacionalizó como el resultado final obtenido al concluir el ciclo lectivo: aprobado o reprobado. De los estudiantes participantes 102 (65%) obtuvieron un rendimiento académico exitoso, y 49 (31%) consideraron pertenecer a familias funcionales. Casi la mitad de los participantes, 88 (56%) opinaron que no varió su funcionalidad familiar a través del tiempo. Se hicieron 2 mediciones de funcionalidad familiar y al no encontrarse diferencia significativa entre ellas, Ji-Cuadrado de McNemar 7.686, p = . 262, se tomó la segunda medición para analizar su relación con rendimiento académico. No se encontró relación entre las variables estudiadas (p =. 177), por lo que deberían efectuarse otros estudios para definir los factores que contribuyen en un rendimiento académico exitoso.