The aim of this study was to determine whether the need for tenotomy can be predicted at the initiation or during the treatment of the clubfoot treatment according to the Ponseti method. One hundred and eight feet of 77 babies who required tenotomy and who did not were compared statistically according to the parameters of sex, side, bilaterality, presentation day, number of casts, Pirani scores, and the percentage change in Pirani scores, respectively. The mean number of casts required, the initial Pirani scores, and the percentage change in Pirani scores were significantly different between the groups that required tenotomy and the groups that did not (P=0.0001). Pirani scores at the beginning and the percentage change in Pirani scores during the treatment can be used to estimate the need for Achilles tenotomy.