Renal osteodystrophy is very rare in undialysed chronic renal failure in Israel, and common in Western Europe and North America. In a dietary survey it was found that there was a lower dietary phosphorus intake in Israel (942 ± 23.1 mg/ day) compared to a mean of 1,238 ± 65.0 mg/day in the UK in healthy subjects on their normal diet, whereas the daily intake of calcium was higher in Israel (1,071 ± 58.5 mg/day) compared to 887 ± 33.5 mg/day in the UK. In an investigation of non-dialysed chronic renal failure patients in Israel it was found that at all levels of renal failure in Israel plasma phosphate levels were lower than in a personal series from England and that plasma calcium levels were more frequently lower than in the UK or USA series. The plasma Ca × P product was below 70 in all cases in Israel. The data were interpreted as indicating that a lower P load in Israel resulting from a lower protein intake results in a lower plasma phosphate level at all levels of renal failure and so the development of hyperparathyroidism is delayed until a very late stage of renal failure. The results are compatible with the Bricker ‘trade-off’ hypothesis suggesting that a reduction of phosphorus intake daily in renal disease may prevent the development of renal osteodystrophy.