Seventy cytology specimens, including fine-needle aspirates from various sites, body effusions, and bronchoalveolar lavages were prepared with a cell block system. This technique, which uses a gelling reagent and a setting reagent to increase the recovery of material, is described in detail. Fifty-four cases had adequate material. To assess the efficacy of the technique, miniblock sections were compared with smears. In 23 cases (43%), the sections provided additional information for a definite diagnosis. The technique allows the recovery of minute cellular material and is valuable for histochemical and immunohistochemical studies.