Preparing desired smooth specimens from pyroclastic rocks is difficult and time consuming for some standard tests such as uniaxial compressive strength (UCS) test, since they are weak or soft rocks. For this reason, the development of some equations is important for predicting the UCS of pyroclastic rocks. A linear correlation was suggested for the prediction of UCS from block punch index (BPI) test for a wide range of rock in the literature. The UCS-BPI conversion factor for this correlation is 5.1. In this study, the relation between UCS and BPI was investigated for pyroclastic rocks. Twenty-eight different samples of pyroclastic rocks were collected from the Cappadocia Region of Turkey. The UCS and BPI tests were carried out on the oven-dried samples in the laboratory. The test results were analyzed using the method of least squares regression. The linear regression analysis showed that the UCS-BPI conversion factor for the tested rocks was 3.1. This value is fairly lower than the suggested value. On the other hand, the correlation coefficients of power law functions are higher than that of the linear functions. Concluding remark is that the UCS-BPI conversion factor for the pyroclastic rocks is lower than the suggested general conversion factor and the UCS-BPI relation is best represented by the power law function.