The Distributed Energy Resources (DER) emerged as an alternative to centralized generation since it presents numerous economic and operational benefits, such as, power loss reduction, voltage profile improvement, and relieved system's congestion. These benefits can be obtained by optimized sizing and placement of the DER; however, an improper DER integration can generate problems regarding the levels of current, voltage and power factor of the network. In this paper, the Cuckoo Search (CS) metaheuristic algorithm was applied to solve the allocation and sizing problem in IEEE 13 and 34 node test feeders in order to improve the voltage profile. The results were compared with the Particle Swarm Optimization (PSO) and Genetic Algorithms (GA) with the purpose of validating the CS method. Finally, it was possible to conclude that CS algorithm presented satisfactory results, meeting all constraints regarding the amount of DER, voltage levels and operational limits.