Vitamins B complex and homocysteine has been given much attention as preventive factors against cognitive decline and dementia. Hyper homocysteinaemia has been suggested as a cause or mechanism in the development of Alzheimer's disease and other forms of dementia. The present study is designed to know the role of vitamin B complex and homocysteine and its relation with cognition, using biological samples. A total of 337 subjects with a mean age of 49 years participated in the cross sectional study from different parts of Kerala state in India. Participants were administered a series of neuropsychological test batteries with major emphasis on 7-min screen test. All test procedures were administered by standard protocol after a written consent was obtained from the participating subjects. Analysis of vitamin B complex and homocysteine was done, using serum samples and the data obtained was then statistically analyzed using statistical package for social sciences (SPSS) software version 17. Vitamin B 6 and B 9 were found to be significantly related to the cognitive score (P < 0.001, p < 0.003, respectively). Independent sample test showed a highly significant change with a p value < 0.048 and < 0.019 of vitamin B 12 and homocysteine, respectively. The results of our study give us an insight that Vitamin B complex and homocysteine may be closely associated with cognitive function in elderly population. But further studies on a larger population is required to come out with a definite conclusion.