We report a quantum key distribution (QKD) system that uses light-emitting-diodes (LEDs) at 1310 nm as optical sources. Compared to the normally used laser diodes (LDs), LEDs are easier to manufacture and integrate, and thus have the potential to reduce the costs of practical systems. To demonstrate the feasibility of a low-cost, integratable QKD system that aims at meeting the demand of the last-mile secure communication, we utilize LEDs at 1310 nm as the optical sources, while using only passive optical components and only one single photon detector at the receiver’s side. With a repetition rate of 10 MHz, we obtain secure key rates of 10.9 kbps within the experimental time of 1000 s over a fiber length of 1 km.