BACKGROUND: Hypertrophic scars result from excessive collagen deposition and increased transforming growth factor beta-1 (TGF-beta1) levels. We hypothesized that the expression of TGF-beta1 mRNA and protein would increase with the clinical severity of hypertrophic scars. METHODS: Primary dermal fibroblasts were isolated from cultures of normal skin and hypertrophic scars. The hypertrophic scars were classified by grade based on the Vancouver Scar Scale. After 96 hours of serum starvation, TGF-beta1 levels in the supernatant were determined using solid-phase, enzyme-linked immunosorbent assay (ELISA). Quantitative reverse transcription-polymerase chain reaction was performed to quantify TGF-beta1 mRNA expression. RESULTS: TGF-beta1 protein levels of hypertrophic scars tended to increase with increasing severity of the scars, according to the Vancouver Scar Scale. The differences between the normal dermal tissue (NS), hypertrophic scar grade (HS) 1, and HS4 groups were statistically significant (P<0.01). The TGF-beta1 mRNA levels of hypertrophic scars also tended to increase according to scar severity. The differences between the NS, HS1, HS2, HS3, and HS4 groups were statistically significant (P<0.01). CONCLUSIONS: The classification of hypertrophic scars according to the Vancouver Scar Scale usually matches the severity of the microenvironment of the hypertrophic scar.