This study is being conducted to comply with the Food and Drug Administration (FDA) recommendation that all new non anti-arrhythmic drugs be assessed for cardiac repolarization effects through electrocardiographic evaluation. Therefore, this study will evaluate the effect of GSK1265744 on cardiac conduction as assessed by collection of twelve-lead continuous digital data in healthy adults. This study will evaluate the effect of three doses of GSK1265744 on the QT duration corrected for heart rate (QTc) interval as compared to placebo. Moxifloxacin will be used as a positive control in order to validate the sensitivity of the study in detecting QTc change. This study consists of three treatment periods (each separated by 21 day washout period) followed by follow-up visit 10 to 14 days post last dosing. The total duration of study including follow-up visit will be approximately 62 days. Approximately 42 subjects will be enrolled such that 34 subjects complete dosing and critical assessments.