Abstract: Supply of safe vaccines is very important and appropriate procedures, monitoring and logistics systems need to be put in place to ensure safety. The pharmaceutical supply chain have various global regulatory requirements to be met during transport ,storage, packaging and handling environmentally sensitive products like biologicals, vaccines and some medicines. This is to ensure that quality and efficacy of cold chain products is not compromised along the supply chain. Global players have regulations and guidelines that address product integrity and safety during the entire supply chain. It was therefore of importance to identify how Pharmaceutical distributors in Nairobi County have developed their cold chain supply systems and how it is able to maintain cold chain for temperature-sensitive pharmaceuticals considering the challenges of; Transport systems, storage facilities, packaging, technical capacity, unreliable electricity supply, weak validation systems, probable poor monitoring of cold chain supply systems. The main objective of the study was to establish the influence of supply chain logistics in supply of safe pharmaceutical cold chain products in Pharmaceutical distributor firms in Nairobi County while the specific objectives were to determine how storage conditions in pharmaceutical distributors in Nairobi influences safety of vaccines; to determine the influence of transport systems on the safety of vaccine; to evaluate the influence of Packaging on the safety of vaccines and finally establish the extent to which technical capacity influence safety of Vaccines in pharmaceutical distributors in Nairobi.