In recent years, various types of molecular imaging technologies have been developed, but many of them require probes and may have some influence on the distribution of the target molecules. In contrast, Raman microscopic analysis is effective for molecular identification of materials, and molecular imaging methods employing Raman scattering light can be applied to living organisms without use of any exogenous probes. Unfortunately, Raman microscopic imaging is rarely used in the biomedical field due to the weakness of Raman signals. When the conventional Raman microscopes are used, the acquisition of an image of a cell usually takes several hours. Recently, a slit-scanning confocal Raman microscope has been developed. It can acquire images of living cells and tissues with faster scanning speed. In this study, we used the slit-scanning confocal Raman microscope (RAMAN-11) to image the distribution of a drug in living cells. We could acquire images of the distribution of an anticancer reagent in living cells within several minutes. Since the wavelength of Raman scattering light is determined by the frequency of molecular vibration, the in situ mapping of the intracellular drugs without use of a probe is possible, suggesting that laser Raman imaging is a useful method for a variety of pharmacokinetic studies.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.