Hypertrophic cardiomyopathy (HCM) represents a generalized myopathic process affecting both ventricular and atrial myocardium. We aimed to assess left atrial (LA) function by two-dimensional speckle tracking echocardiography and its relation with left ventricular (LV) function and clinical status in patients with HCM. We prospectively enrolled 37 consecutive patients with HCM and 37 normal subjects with similar age and gender distribution. Longitudinal LV strain (ε) and LA ε and strain rate (Sr) parameters (systolic, early diastolic, and late diastolic during atrial contraction) were assessed. Peak LAε and LA Sr parameters were significantly lower in patients compared with controls (P ≤ .001 for all). In patients, all LA function parameters correlated with LVε (P < .003 for all). Indexed LA volume, LA function parameters, and mitral regurgitation degree were the main correlates of New York Heart Association class; late diastolic strain rate during atrial contraction was the only independent predictor of symptomatic status. In patients with HCM, LA function is significantly reduced and related to LV dysfunction. Moreover, LA booster pump function emerged as an independent correlate of heart failure symptoms in this setting.