The vibrational spectra of aniline(H2O)(n)(+) (n = 2-6) in the 3 mum region have been measured. Cluster cations were generated by near resonant two-photon ionization of neutral clusters, and magic numbers were observed at n = 4 and 5. The infrared spectra were investigated with the aid of the B3LYP/6-31++G** method, It was found that several isomers coexisted. A linear type cluster is the main component for the small clusters. A ring type cluster in which the NH2 group of aniline and water molecules form a ring appears in the spectrum of the clusters of n = 3, and it becomes the main component in the clusters of n greater than or equal to 4.