El inicio temprano del consumo de alcohol se relaciona con el desarrollo de un patrón de consumo riesgoso y de problemas relacionados al consumo. Dada la importancia de desarrollar modelos conceptuales integrales y longitudinales se analizó el efecto prospectivo de diferentes variables sobre el consumo de alcohol adolescente (CAA). Participaron 332 adolescentes que completaron escalas para medir rasgos de personalidad, expectativas hacia el alcohol (EA), motivos de consumo de alcohol (MC), consumo de alcohol de pares (CP) y padres, apoyo parental y CAA. Se realizaron dos administraciones, al inicio y 12 meses después. Se aplicó la técnica de path análisis para determinar el efecto prospectivo de los factores implicados. Los rasgos de personalidad y las EA positivas tuvieron un menor efecto, mientras que el CAA inicial, el CP y las EA negativas fueron importantes predictores del CAA. Los MC fueron el antecedente más próximo del consumo. Se destaca la importancia de considerar múltiples variables para obtener una explicación más completa de este fenómeno. La fuerte influencia del CAA inicial sugiere que, una vez desarrollado  un patrón de consumo de alcohol, es muy probable que este consumo se mantenga o aumente.The early drinking onset is related to hazardous drinking patterns (DP), which in turn increases risk for alcohol- related problems and disorders, later in life. It is highlighted the importance of developing conceptual and longitudinal models that integrate the contribution of different variables. The prospective effect of different factors on future adolescents' DP was analyzed. A sample of 332 high- school adolescents participated in this study. Scales to measure personality traits, alcohol expectancies (AE), drinking motives, peers and parental alcohol use, participants' DP, and perceived social support were used. Instruments were administered at baseline and twelve months later. A path analysis showed that most of the factors had a significant effect upon future DP. Personality traits and positive AE had the lowest effect, while DP at baseline, peers' drinking and negative AE were the most important predictors of future DP. It's emphasized the importance of considering multiple variables when trying to explain adolescents' drinking behaviors in a comprehensive way. The strongest effect of prior DP suggests that once adolescents developed a pattern of alcohol consumption it is highly probable they maintain or increase their drinking.