Aims: We studied the long-term effects of peri/neonatal factors and growth on BMD in prematurely born children at 5-7 years .2.Subjects: 40 children, mean gestational age (ga) 31(25-36)wks, 18 boys/22 girls:A) those born ≤ 33 wks (n = 27) got calcium carbonate 120-130 mg/kg/day, sodiumdiphosphate 40-45mg/kg/day, vit.A 1000IU/day, vit.D 400IU/day, vit.C 2mg/kg/day till weight reached 2.5 kg or until dischargeB)those born > 33 wks(n = 13) got only vit.D 400IU/day .3.Measurements: Lumbar spine (L2-L4)BMD(LsBMD)(mineral content(g)/the area scanned) was measured by dual energy absorptiometry by Lunar DPX. Weight% = percentage of weight at 1 year from the present weight was calculated to assess rapidity of 1 st year catch-up growth. Relations between LsBMD (dichotomized to values ≤25% tile and >25% tile) and other variables were studied by log.regression. 4.Results: There was no difference in mean LsBMDs between group A [0.643(0.08)], group B [0.663(0.06)] and reference data. LsBMD correlated negatively with weight% (r =-0.5631; p =< 0.001)even when controlled for the effects of children's present size and age. Log. regression showed that the only significant determinant of LsBMDs was weight%, ga and other factors had no effect .5.Conclusions: Rapid catch-up growth during the 1st year was associated with LsBMD below 25%tile in prematurely born children at 5-7 yrs. Thus, mineral supply should be adequate not only at neonatal period but throughout infancy.