This study aims to investigate the evolution and factors associated with TAC IPV and its impact on patient outcomes in pediatric LT recipients. This is a retrospective study including 41 children. The TAC IPV was expressed as the coefficient of variation and was calculated for years 1-5 following LT. The number of missed clinic appointments was used as a surrogate marker for therapy adherence. We identified a decrease in the TAC IPV during the first 3years after LT (P<0.01). Serum albumin in the first year (P=0.03), hematocrit (P=0.02) and total bilirubin (P=0.04) in the third year, and therapy adherence (P<0.01) in the fifth year were associated with TAC IPV. High TAC IPV was associated with biopsy-proven acute allograft rejection (P=0.04) and the need for biopsy during the first year (P=0.02). There was a borderline association between TAC IPV and donor-specific antibodies (P=0.08) and CMV viremia (P=0.07). High TAC IPV was a predictor of need for liver biopsy and AR with an odds ratio of 1.04 (95% CI 1.0-1.1; P=0.03) and 1.04 (95% CI 1.0-1.1; P=0.05), respectively. Our results highlight the impact of biological factors on TAC IPV during the early LT follow-up and later also therapy adherence. High TAC IPV may be associated with adverse patient outcomes.