summary By means of literature search, an overview of neuroimaging research on dopamine D2 receptor occupancy by antipsychotic medication has been framed. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) techniques are useful to deter-mine the occupancy of dopamine receptors by antipsychotic drugs in vivo. Clozapine and possibly quetiapine appear to result in low D2 receptor occupancy though being effective. These techniques have led to a better insight in the relation between dosages of antipsychotic drugs, therapeutic effect, and the occurrence of extrapyramidal side effects.