A miniature, wideband, horizontal-component feedback seismometer has been developed and compared with conventional seismometers. The instrument employs an inverted pendulum of mass 0.04 kg supported with a natural period of 0.6 s and a Q factor of about 20. Displacements of the mass are sensed by a differential capacitive transducer and feedback is applied via an electromagnetic system to maintain the mass stationary with respect to its supports. The instrument has a response defined by feedback from DC to 100 Hz and has a Brownian noise level of 5*10^-10 m s^-2. Overall dimensions, including an evacuated jacket, are 15 cm*10 cm diameter making it suitable for borehole applications. The instrument has been operated for several weeks with conventional long-period seismometers and has been found to compare satisfactorily.