This document presents an approach called Translation Data Augmentation (TDA) to improve neural machine translation, especially for low-resource languages. TDA generates additional training sentences by altering existing parallel sentences to target rare words. This increases the size and diversity of the training data. Experimental results show that training with augmented data significantly improves BLEU scores over the baseline, with gains of up to 2.9 BLEU points for a simulated low-resource English-German translation task. TDA particularly helps with translating low-frequency words, which neural models often handle inaccurately due to lack of data.