Six single-cell clones, 3 from the grape stem callus and 3 from the gall tissue, incited by Phylloxera vastatrix Planch were grown on a modified White''s medium supplemented with growth substances and coconut milk. Growth of the clones was measured as wet weight, dry weight, and cell count at intervals of 5 days during growth periods of 10-40 days. The clones were differentiated into 3 groups: fast-, medium-, and slow-growing. Results of all the methods were comparable. The highest percentage increase in wet and dry weight per day, and the largest number of cells per milligram of the fresh weight of the tissues was recorded in the 1st reading taken on the 10th day. This was followed by gradual decrease. In general, clones of both gall and normal origin maintained uniformity in their specific growth patterns. More striking differences were observed among the normal clones than in the gall clones on the basis of cell counts. The fast-growing clone showed the fewest number of cells among the normal clones. The cells of the fast-growing normal clone had the largest, and the slow-growing gall clone the smallest cells among the 6 clones.