Two techniques have been examined for the direct measurement of minority carrier capture cross sections of deep‐lying impurity states in silicon. Both involved the use of a bipolar transistor structure with which minority carrier flow through the device could be controlled. In one technique the carrier capture transient due to the flow of this minority current was directly monitored, and in the other case the current was simply used to empty centers in the minority carrier half of the band gap of majority carriers prior to employing the conventional diode short‐circuit technique. It was shown by the former technique that the capture cross sections of gold and platinum in silicon are strongly field dependent. In addition, some evidence is presented to suggest that the donor and acceptor levels of platinum in silicon may not be different charge states of the same center. Data are reported on the temperature dependence of the minority carrier cross sections of gold and platinum in silicon. Lifetime measurements in gold‐killed diodes were found to be within a factor of two of the lifetime values calculated using the measured capture cross sections.