Goitre prevalence and mental performance were determined amongst the Aborigines in Sinderut, a remote rural area in Pahang. A total of 196 subjects aged 4 to 60 years old were selected for study. Goitre status was determined by an experienced endocrinologist using classification suggested by World Health Organization; while mental performance was measured using Raven's test (Oxford Psychologists Press). Blood specimen was also taken for thyroxine (T4) and thyroid stimulating hormone (TSH) measurement. It was found that goitre prevalence was 26.5% (52/196); with visible goitre prevalence of 42.3% (22152). The overall mean of goitre volume was 21.4 ± 19.1 ml (range: 3.0 - 90.8 ml), while the prevalence of mental performance for the percentile value of more than 5.0 was 26.5% (range: 5.0 - 50.0). Mean thyroxine levels was 75.4 ± 19.3 nmol/L (range: 19.9 - 138.1 nmol/ L) while mean levels of thyroid stimulating hormone was 4.9 ± 3.2 mU/L (range: 0.4 - 18.9 mU/L). There was no significant correlation between hormone levels and mental performance score (Pearson Correlation; T4 : r=-0.002, p=0.9736; TSH : r=0.10, p=0.1843). goitre volume and mental performance score (Pearson Correlation; r=-0.02, p=0.8395). Goitre prevalence of more than 20% in this area indicates a moderate endemia, while mental performance showed a low thinking level in the Aborigines particularly those who lived in remote areas.