Abstract: Gamma-aminobutyric acid type A-benzodiazepine receptors are heterogeneous polypeptide pentamers widely spread in the central nervous system on the neuron membrane. Different subunit combinations educe various neuro-inhibitory pharmacological effects such as sedative, hypnosis, anticonvulsion and anxiolysis. PET can be utilized to study the binding of the receptors in vivo. PET radioligands of gamma-aminobutyric acid type A-benzodiazepine receptors can be classified into 3 types: antagonists, agonists and reverse agonists, of which antagonist radiotracer ¹¹C-flumazenil is the most commonly applied in epilepsy, anxiety disorders, depression, vegetative state, addiction and other neuro-psychiatric disorders.