Dendrite coherency or dendrite impingement is an important factor for determining solidification microstructure and casting defects of alloys. In this research, the effect of various cooling rates and Al-5Ti-1B grain refiner contents on the dendrite coherency point (DCP) characteristics of an Al-Si-Mg alloy designated as A357 has been studied. The results showed that both mentioned parameters have a significant influence on DCP of this alloy. Increasing the cooling rate from 0.15 to 1.0 °C/s and the grain refiner content from 0.0 to 3 wt. % increased the solid fraction in where dendrite coherency occurs. Moreover, enhancement of the cooling rate and grain refiner could increase the difference between the liquidus and coherency temperatures (T_N–T_DCP), about 27 and 26 °C, respectively. The dendrite coherency time decreased by increasing the cooling rate and increased by increasing the grain refiner content.