The neurotransmitter acetylcholine (ACh) exerts its effects on the central nervous system (CNS) and peripheral nervous system (PNS) through two distinct types of receptors: the muscarinic and nicotinic ACh receptors (mAChRs and nAChRs, respectively). The five mAChR subtypes m1-m5 belong to the superfamily of G-protein-coupled receptors and mediate the slow metabolic responses to ACh via coupling to second messenger cascades, whereas the nAChRs are ligand-gated ion channels mediating the fast synaptic transmission of the neurotransmitter. The nAChRs are involved in a wide range of physiological and pathophysiological processes. The muscle-type nAChR is localized postsynaptically at the neuromuscular junction, where it is a key mediator of the electrical transmission creating the skeletal muscle tone, and thus, it is the target of several clinically used muscle relaxants. The numerous neuronal nAChR subtypes are located at presynaptic and postsynaptic densities in autonomic ganglia and in cholinergic neurons throughout the CNS, where they are involved in a number of processes connected to cognitive functions, learning and memory, arousal, reward, motor control, and analgesia. Equally important to the overall contribution of nAChRs to cholinergic neurotransmission are the roles of presynaptic and preterminal nAChRs as autoreceptors and heteroreceptors regulating the synaptic release of ACh and other important neurotransmitters such as dopamine (DA), norepinephrine (NE), serotonin (5-hydroxytryptamine, 5-HT), glutamate (Glu), and γ-aminobutyric acid (GABA). It is primarily because of their modulatory input to these neurotransmitter systems that neuronal nAChRs have been proposed as potential therapeutic targets for the treatment of pain, epilepsy, and a wide range of neurodegenerative and psychiatric disorders such as Alzheimer's disease, Parkinson's disease, Tourette's syndrome, schizophrenia, anxiety, and depression. Furthermore, somatic mutations in nAChRs have been linked to certain forms of epilepsy and schizophrenia. Finally, nAChR ligands have also been suggested for the treatment of drug addiction, and systemic nicotine administration is the predominantly used smoking cessation aid today. The heterogeneity of the native nAChR populations in the CNS presents major possibilities as well as challenges in terms of developing therapeutics targeted at these receptors. The fact that several important physiological processes appear to be regulated by a single or a few nAChR subtypes makes it possible to target specific functions without affecting other aspects of cholinergic neurotransmission. Furthermore, since the well-documented cardiovascular and gastrointestinal side effects of nicotine and other nonselective nAChR agonists as well as the potential addiction liability of these compounds also seem to be mediated by specific nAChR subtypes, pharmaceutical agents acting on distinct subpopulations of nAChRs might be devoid of these side effects. The perspectives of rational design of these agents are, however, faced with at least two major obstacles. First, the design of subtype-selective nAChR ligands is complicated by the homologous nature of the receptor proteins, as especially the regions forming the orthosteric sites (the ACh binding sites) in the receptors are characterized by high degrees of amino acid sequence identities. Second, the identification of the exact molecular compositions of specific native nAChR subtypes modulating the synaptic release of different neurotransmitters in different CNS regions has been complicated by the staggering number of nAChR combinations that can be formed from the neuronal nAChR subunits. A prerequisite for rational drug design is definition of one's target based on its physiological expression and function as well as a basic understanding of the molecular architecture of the particular protein. In this Perspective, the insights into neuronal nAChR structure and function obtained from recently published highresolution X-ray structures of proteins pertinent to these receptors will be outlined, and the perspectives of rational design of nAChR selective ligands offered by these structures will be discussed. Furthermore, recent advances in the identification of native nAChR subtypes of potential therapeutic interest and examples of currently available subtype-selective nAChR ligands will be presented.