Rapid manufacturing using 3-D printing is a potential solution to some of the most pressing issues for humanitarian logistics. In this paper, findings are reported from a study that involved development of a new type of 3-D printer. In particular, a novel 3-D printer that is designed specifically for reliable rapid manufacturing at the sites of humanitarian crises. First, required capabilities are developed with design elements of a humanitarian 3-D printer, which include, (1) fused filament fabrication, (2) open source self-replicating rapid prototyper design, (3) modular, (4) separate frame, (5) protected electronics, (6) on-board computing, (7) flexible power supply, and (8) climate control mechanisms. The technology is then disclosed with an open source license for the Kijenzi 3-D Printer. A swarm of five Kijenzi 3-D printers are evaluated for rapid part manufacturing for two months at health facilities and other community locations in both rural and urban areas throughout Kisumu County, Kenya. They were successful for their ability to function independently of infrastructure, transportability, ease of use, ability to withstand harsh environments and costs. The results are presented and conclusions are drawn about future work necessary for the Kijenzi 3-D Printer to meet the needs of rapid manufacturing in a humanitarian context. Yet, supply chain logistics for humanitarian responses are some of the most complex that exist. It is challenging to forecast both the demand (due to difficulties in knowing both the timing of a disaster and details of the population affected) and the supply, which is often fueled by donations [4]. A massive mismatch between the supplies delivered and the supplies that are needed is often inevitable both in quantity and kind [2,3,5]. As 60-80% of all aid money is spent on procurement, this mismatch represents not only costly errors but errors that can have negative long-term effects on local markets and economies [5].Rapid manufacturing using 3-D printing is a potential solution to some of these pressing issues in humanitarian logistics. This has become potentially feasible with the open source 3-D printers developed from the self-replicating rapid prototyper (RepRap) project [6][7][8]. The RepRap project has driven down costs of 3-D printing to fit resource-constrained contexts like those found in the developing world or during a crisis [9]. The potential for 3-D printers in humanitarian aid work has been able to capture the interest of practitioners in the field [10], as 3-D printing can have positive effects on nearly every step of the humanitarian supply chain [5].3-D printing can reduce time and money used in the procurement of goods [11,12] by reducing the amount of capital required for manufacturing at a given location, allowing distributed manufacturing [13][14][15] or more localized manufacturing to occur [3,10]. By manufacturing goods locally at the site of a disaster response, the only materials that need to be shipped to the site of a disaster are the raw materials needed...