This invention relates to compounds, compositions, and methods useful for modulating protein tyrosine phosphatase-1B (PTP-1B) gene expression using short interfering nucleic acid (siNA) molecules. This invention also relates to compounds, compositions, and methods useful for modulating the expression and activity of other genes involved in pathways of PTP-1B gene expression and/or activity by RNA interference (RNAi) using small nucleic acid molecules. In particular, the instant invention features small nucleic acid molecules, such as short interfering nucleic acid (siNA), short interfering RNA (siRNA), double-stranded RNA (dsRNA), micro-RNA (miRNA), and short hairpin RNA (shRNA) molecules and methods used to modulate the expression of PTP-1B genes. Such small nucleic acid molecules are useful, for example, for treating, preventing, inhibiting, or reducing obesity, insulin resistance, diabetes (eg. type II and type I diabetes) in a subject or organism, and for any other disease, trait, or condition that is related to or will respond to the levels of PTP-1B in a cell or tissue, alone or in combination with other treatments or therapies.