Introduction: There are many techniques for the caseous chronicle tonsillitis surgery. The most recent described by Krespi, 1993, deals with CO2 laser cryptolysis. Objective: To evaluate the efficiency of this technique in only one surgical procedure, demonstrating through microscopy the persistence or not of crypts after the surgery. Methods: Ten patients with chronic tonsillitis, ranging from 18 - 35 years old were selected. All were submitted to CO2 laser tonsillectomy, under local anesthesia, 10W, continuous pulse. Randomly, one of the palatine tonsils was previously submitted to CO2 laser cryptolysis, according to Krespi’s technique. All 20 removed palatine tonsils (10 submitted to CO2 laser cryptolysis and 10 not) were histological examined by light microscope and their crypts were measured. Results: There was a statistically significant reduction of tonsils crypts submitted to CO2 laser cryptolysis, but they did not disappear at all. In one of the cases, it was possible to observe food debris inside the crypt. Conclusion: After one session of CO2 laser cryptolisis, there was an important reduction of the crypts size using light microscope examination, but not enough to eliminate them.