传输electron microscopy (TEM) is a microscopy technique that can produce very high magnification and resolution images compared to standard light microscopy.

TEM uses electrons instead of light as a radiation source and involves passing an electron beam through an ultra-thin section of the specimen giving rise to black and white, two-dimensional cross-section images.

TEM is useful for investigating the structure of macromolecular complexes, organelles, cells and tissues, and is used in preclinical safety evaluation and mechanistic studies where visualization of subcellular structures can be used to determine functional changes and give information relevant to other safety endpoints.