[en] 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 β_c (β_c ≈ 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 ∂ V/∂ Φ larger than 420 μV/Φ _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 210×210 mm"2. MCG measurements with a high signal-to-noise ratio of 40 dB were done successfully using the developed system. (paper)