A technique used to collect haemolymph of the tomato leafminer; Tuta absoluta (Lepidoptera) fourth larval instar was described. It depends on centrifugation of the larvae at a given speed. This technique has the advantage that it enables collecting blood from T. absoluta larvae whereas manual expression of blood from the cut ends of prologs is impossible. Approximatry 11 µl of haemolymph from 8-10 larvae were collected after centrifugation for 10 min at 1500 r.p.m.. The chemical characteristics of haemolymph plasma collected were studied. The haemolymph of the tomato leafminer contains 29.27, 390, 79, 440, 62.5 and 137.5 µg / ml of chloride, phosphorus, calcium, magnesium, sodium and potassium, respectively. Na: k ratio was 0.45, indicating the presence of low sodium index as an advanced feature like other Lepidopterans. The measured high magnesium content, and alkaline pH (=7.3) might be due to T. absoluta food habit as aphytophagous insect.In general, the main characteristics of the tomato lefminer are more or less similar to that of other species of Lepidoptera.  The centrifugation technique is an efficient method to collect blood from small insects, but the optimal velocity of centrifugation must be detected for each species.