It is known that a spectrum of changes in structure, size and function of the different chambers of the heart occur in individuals with hypertension. The changes in the left ventricle and left atrial sizes are believed to be collinear. The earliest changes and the sequence of these changes are still being studied. OBJECTIVES The study was carried out to assess how early changes in the left atrial size and function occur in hypertension, to determine the relationship between the size of the left atrium and left ventricular geometry and to determine the factors that influence left atrial size. METHODS Transthoracic echocardiography was performed in hundred (100) newly diagnosed patients with hypertension and in fifty (50) normal individuals to assess the left ventricular geometry, the systolic function using the ejection fraction, Doppler mitral inflow velocities and pulmonary venous flow velocities. The endocardial border of the left atrium was traced to obtain the atrial area and left atrial volumes and emptying fraction were derived from measured areas. RESULTS There was no statistically significant difference between age, sex and body mass index of the patients with hypertension and normal controls. Thirty seven (37%) of the hypertensive subject had increased left ventricular mass against eight subjects (16%) in the normal controls. The group with hypertension had thicker septum, higher left ventricular mass and relative wall thickness. The ejection fraction was comparable between the two groups, 73.2(14.13) in the subjects with hypertension and 74.3(9.91) in the normal control group. The patients with hypertension had a higher linear left atrial dimension and a longer pre-atrial contraction length. Peak atrial mitral inflow velocity was significantly higher in the subjects with hypertension. Body weight, body mass index, left ventricular end diastolic diameter were all correlated to left atrial size. Only weight independently influenced left atrial size. CONCLUSION Changes in the left ventricle such as increased left ventricular mass, septal hypertrophy and increased relative wall thickness occur early in hypertension and precedes deterioration in left ventricular systolic function. The corresponding left atrial changes are marginal and are indicative of accentuated atrial systolic function