Pharmaceutical compositions and methods are described comprising at least one peptide YY compound and one or more intranasal delivery-enhancing agents for enhanced nasal mucosal delivery of the peptide YY, for treating a variety of diseases and conditions in mammalian subjects, including obesity. In one aspect, the intranasal delivery formulations and methods provide enhanced delivery of peptide YY to the blood plasma or central nervous system (CNS) tissue or fluid, for example, by yielding a peak concentration (C.sub.max) of the peptide YY in the blood plasma or CNS tissue or fluid of the subject that is 20% or greater compared to a peak concentration of the peptide YY in the blood plasma or CNS tissue or fluid of the subject following administration to the subject of a same concentration or dose of the peptide YY to the subject by subcutaneous injection.