LiMn2O4 (LMO) powders were prepared by modified chemical bath deposition method. The effect of reaction time on the structure, morphology and optical properties of LMO nanostructures were investigated. The reaction time was varied from 1 - 120 min. The X-ray diffraction (XRD) patterns of the powders correspond to the various planes of a cubic spinel LMO phase. It was observed that the secondary phases decreases with an increase in reaction time. The diffraction peaks increase in intensity with an increase in reaction time up to 10 min. The estimated average grain sizes calculated using the XRD spectra were found to be in the order of 60 ± 1 nm. The scanning electron microscope (SEM) image suggested that the reaction time influences the morphology of the prepared powders. The irregular nanoparticle increased in size with an increase in reaction time. The UV-Vis spectra showed a red shift with an increase in reaction time up to 10 min.