This study attempts to find the best fitted distribution function to the minimum D-day low flows for the Meric and Sakarya river basins in Turkey. For this purpose, the W2 and LN2 distribution functions were used. The Probability Plot Correlation Coefficient (PPCC) test was applied for the suitability of the selected distribution functions. It was found that the W2 distribution function conformed better than the LN2 distribution function on a station basis. A regional hypothesis test was applied to the 7-day low flow value which is the generally accepted low flow index. Similarly, the W2 distribution performed better than the LN2 distribution in both regions.