This paper describes the termination pattern and synaptic connectivity of the pathway from the basolateral nucleus of the amygdala (BLA) to the medial prefrontal cortex (mPFC; areas 25, 32, and 24b) of the rat. Discrete injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L) were made in the BLA and detailed light microscopical observations made of the distribution of PHA-L labelled fibres and boutons in the mPFC. Labelled fibres were distributed in two tiers: predominantly within deep layer 1/layer 2 and also in layers 5/6. Fibre plexi in layers 2 and 5 were highly varicose. Electron microscopical examination of 120 labelled boutons in area 32 (60 in layer 2 and 60 in layer 5) indicated that 116 (97%) established asymmetrical synaptic contacts with dendritic spines and 4 (3%) were in synaptic contact with small dendritic shafts. No significant differences in target structures were found between layers 2 and 5. The results indicate that BLA input to mPFC in the rat predominantly innervates spine bearing dendrites in layers 2 and 5. This suggests that the neuronal operations of these processes are influenced by direct feedforward excitation from the BLA.