Trials carried out at a range of locations in northern Nigeria showed that gross cash returns from mixtures were never less than those from sole groundnuts, confirming results from the main research station at Samaru. In many cases they were considerably higher and in the Northern Guinea Savanna, where the system is most widely practised, showed a high probability of returns greater than the sole crop median. Increasing attention is being paid to haulm yield and the possibility that sole groundnut may be more profitable near large towns because of haulm value.