A novel magnetic polyaniline (PANI)/Fe₃O₄/Ag nanocomposite was successfully synthesized via in situ polymerization induced by ultraviolet irradiation (λ = 254 nm) in the presence of Fe₃O₄ nanoparticles and Ag cations as oxidants. The morphology and structure of the newly prepared nanocomposite was characterized by Fourier-transform infrared spectrometry, X-ray diffraction, energy-dispersive X-ray spectrometry, vibrating sample magnetometry, transmission electron microscopy, field-emission scanning electron microscopy and inductively coupled plasma optical emission spectrometry. The corresponding saturation magnetization for the nanocomposite was about 20.37 emu g⁻¹. The catalytic properties of the nanocomposite were evaluated in the synthesis of biologically and pharmaceutically important pyran derivatives and it was shown to produce high yields, short reaction times and an easy work-up process. The superparamagnetic properties of the nanocatalyst allowed easy separation from the reaction media.