Aims of the present study were to investigate the distribution and morphology of aquaporin 1‐immunoreactive (AQP1‐IR) neurons in the sensory ganglia of the sheep. Double immunohistochemical staining was applied to figure out whether substance P (SP), calcitonin gene‐related peptide (CGRP) and galanin are present in AQP1‐bearing primary afferent neurons. The expression of AQP1 was present only in trigeminal ganglion, whereas in nodose ganglion, jugular ganglion as well as C1–C7 dorsal root ganglia no presence of AQP1 was found. In trigeminal ganglion, 15.4 ± 2.3% of Hu C/D‐IR neurons (pan‐neuronal marker) showed the presence of AQP1. The vast majority of AQP1‐IR trigeminal sensory neurons (approximately 69.6 ± 3.3%, n = 5) were classified as middle in size, 28.6 ± 3.0% of AQP1‐IR neurons were small and only 1.8 ± 0.6% of AQP1‐positive neurons were large in size. Amongst the population of AQP1‐IR trigeminal neurons as many as 58.5 ± 3.9% were immunopositive to SP, 30.7 ± 2.3% showed the presence of CGRP and 10.9 ± 0.2% coexpressed galanin. In trigeminal ganglion, SP‐IR as well as CGRP‐IR (but not galanin‐IR) nerve fibres were found in close neighbourhood of AQP1‐IR neurons. It is concluded that AQP1 is present in certain neuronal subsets of the ovine trigeminal ganglion; however, the exact role of this water channel has to be elucidated.