Neuroimaging techniques are important clinically, to exclude organic disorders as origins of depression. For research, they provide insight into brain structure, function and network organization, indicating the relevance of different brain circuits for certain brain functions and how these are altered in major depressive disorder (MDD). Here, the findings from cross-sectional and longitudinal neuroimaging studies on major depression will be reviewed, focusing on structural, functional and diffusion imaging, as well as MR spectroscopy. Overall, structural, functional and diffusion imaging studies show alterations in networks consisting of the cingulate cortices, prefrontal cortices, amygdala and subcortical regions like the hippocampus and basal ganglia which may play key roles in MDD. Excitatory and inhibitory neurotransmitters as well as glutathione measured using MR spectroscopy were found to be decreased in MDD compared to controls, while membrane turnover is thought to be increased in some regions. Assessing distinct functional deficits associated with different underlying pathophysiological mechanisms, which in turn might inform about different promising therapies, is currently a research direction.