Undernutrition is a senous global problem especially among developing countries. Undernutrition is still common among poor rural children in Malaysia. The School Supplementary Feeding Programme (SSFP) is one of the intervention strategies implemented to improve the nutritional status of children in Malaysia. The objectives of the study are to determine the prevalence of malnutrition, associated factors of underweight, stunting and wasting and to evaluate the effect of School Supplementary Feeding Programme on improving nutritional status among pnmary one children in rural areas of Tum pat and Bachok districts. The study has 2 phases. Phase 1 is a crosssectional study and the Phase 2 is a cohort study. The study was done among primary one children in rural areas of Tumpat and Bachok districts from February 2002 to March 2003. Nine hundred and thirty seven children from 18 primary schools were selected. Questionnaires eliciting socio-economic and demographic informations were answered by the parents. The weight and height of the children were measured three times; before starting SSFP, after 6 months and after 12 months of SSFP. The WAZ, HAZ and WI-IZ were calculated using Epi-Nut Antlll'opometry software (Epi Info version 6). The prevalence of malnutrition were calculated based on cutoff point of zscore < -2 SD as undernutrition and > +2 SD as overnutrition. The school administration chose eligible children to participate in the SSFP. five hundred and forty one children were enrolled in SSFP and 396 were in non-SSFP group. The prevalence of underweight~ stunting and wasting at baseline were 25 .2%, 21.1% and 6.2% respectively. Only 1.1% of children were overweight. In multiple logistic regression analysis, the significant risk factors of underweight were being male children (OR=l.4, P