Defects can be found in parts made using Selective Laser Melting (SLM) due to balling effects and other types of localized irregularities. This study investigates how defects affect the fatigue performance of Ti-6Al-4V samples in an SLM as-built surface finish condition. Fatigue samples were built and heat treated for stress relief. In order to investigate the effect of defects, a series of fatigue samples were designed with built-in cylindrical and double-conical defects. Tests were carried out to correlate maximum stress to the number of cycles to failure. Optical and scanning electron micrographs were utilized to compare and analyze crack initiation and propagation characteristics. Based on the results, the influence of defects on fatigue properties is discussed.