The goal of this project was to determine the effect of different types of music on a dog's heart rate. Six different dogs were tested in their own homes. Each experiment was performed in a quiet room with the dog’s owner present along with the two scientists performing the testing. Five different types of music were used in the experiment. Using a stethoscope, we measured the resting heart rate prior to testing and again immediately following the test. A five-minute break was taken between each test, and two trials were completed for each test conducted. The result was a statistically significant difference in heart rate for rock and rap music (increase) and for jazz music (decrease). A caveat to this study was the relatively small number of dogs tested (six); therefore, future research with a larger sample size should be conducted to confirm these results. This information could help calm dogs in potentially stressful situations, such as the veterinary office or when traveling.