We constructed a 36-channel magnetocardiography (MCG) system based on low-T-c direct current (DC) superconducting quantum interference device (SQUID) magnetometers operated inside a magnetically shielded room (MSR). Weakly damped SQUID magnetometers with large Steward-McCumber parameter beta(c) (beta(c) approximate to 5), which could directly connect to the operational amplifier without any additional feedback circuit, were used to simplify the readout electronics. With a flux-to-voltage transfer coefficient partial derivative V/partial derivative phi larger than 420 mu V/phi(0), the SQUID magnetometers had a white noise level of about 5.5 fT.Hz(-1/2) when operated in MSR. 36 sensing magnetometers and 15 reference magnetometers were employed to realize software gradiometer configurations. The coverage area of the 36 sensing magnetometers is 210 x 210 mm(2). MCG measurements with a high signal-to-noise ratio of 40 dB were done successfully using the developed system.