Relationship of riparian vegetation cover structure and fish community, in two hydrological periods in streams in the river basin “La Vieja”, in the “Eje Cafetero” of Colombia. Objective. We investigated the relationship between the composition, structure and diet of fish community and type of riparian vegetation cover (rvc) in six streams in the river basin “La Vieja” in two hydrological seasons. Materials and methods. The collections were made with electrofishing and “rapiche” on March and May 2010. The composition was evaluated with a similarity analysis. The structure was analyzed through indicators of richness, dominance, diversity and evenness, they were compared using an ANOVA test. The diet was studied with a gastrointestinal contents analysis. Indexes of vacuity coefficient, frequency, volume and food importance were used. We examined the relationship between diet, hydrological season and rvc using a Canonical Correspondence Analysis (CCA). Results. According to similarity analysis, the composition of fish community, cvr and hydrological period are related. In the two hydrological seasons, richness, diversity and equity values were low for the rvc of Guadua plantation and grassland, and high for the Guadua plantation and Coffee plantation, moreover, dominance showed a reverse pattern. An ANOVA showed no statistically significant differences between these indices according to the type of rvc and to hydrological season (P!0,05). According to CCA the diet of fish community is related to rvc and hydrological season. Conclusions. The composition, structure and diet of fish community varies more according to cvr and hydrological period variables than productive system. Probably the neighboring rvc affect composition, structure and diet of fish community.