This study took ELTIS (English language teaching institute of symbiosis in India) as a case study, and aimed at exploring the effects of conscientiousness personality trait and its comprising facets including competence, order, dutifulness, achievement striving, self-discipline and deliberation on the usage of learning strategies. The study involved 300 subjects studying English in different courses of ELTIS in 2011-2012. Two questionnaires of NEO. PI. R, a personality factor test (McCrae and Costa 2005), and SILL, a Strategy Inventory for Language learning (Oxford 1990) were administered. Pearson product moment correlation and t. test were used to analyze the data. The reliability of SILL was. 92 and NEO PI. R was. 86. The results showed that there were significant relationships between conscientiousness and memory strategies (p=. 000), cognitive strategies (p=. 039), Meta cognitive strategies (p=. 000), and affective strategies (p=. 018). Order as a facet of conscientiousness was in a correlation with memory, meta cognitive and affective strategies. Achievement striving was an effective factor on memory, cognitive, meta cognitive and affective strategies. Self-discipline had a relationship with memory, cognitive, meta cognitive and social strategies. Deliberation was found only to be effective in meta cognitive strategies. Therefore, conscientiousness personality trait and its facets are effective factors in the selection, usage and frequency of using language learning strategies.