A study of growth rates of NaClO 3 and NaBrO 3 has been carried out using a small growth cell by in situ observation. Normal growth rates of {100} faces of NaClO 3 and {111} faces of NaBrO 3 along 〈 〈110〉 〉 direction are measured under relatively high supersaturation ranging from 3-8%. In the initial stages of growth, {100}, {110} and {111} faces develop in NaClO 3 and gradually all the faces are replaced by the {100} faces only. In the case of NaBrO 3 , mostly {111} faces develop with occasional occurrence of small {100} faces at the intersection of {111} faces. The growth mechanisms are investigated from growth rate vs supersaturation plots and from the observations of surface features. In the present supersaturation range, the growth mechanism appears to be due to two-dimensional growth mechanism.