A vector model based information retrieval of handwritten medical forms is presented in this paper. In order to improve the IR performance on the erroneous output of handwriting recognition (HR) systems, a variation of the vector model is made to estimate the number of occurrences of terms from word segmentation and recognition probabilities. IR Tests show that our approach outperforms the retrieval of ordinary HR text in terms of mean average precision (MAP), R-Precision, and interpolated 11-point precisions.