The band spectrum of SrI is excited in a radio-frequency discharge through a mixture of heated strontium metal and iodine vapour in the presence of argon. The spectrum photographed under high dispersion (1.25 AA mm^-1) reveals the existence of a doublet system of bands degraded to longer wavelengths in the region lambda lambda 4500-4200 AA. The bands are analysed and attributed to a C² Pi -X² Sigma transition with a doublet interval of about 557.3 cm^-1. Vibrational quantum formulae representing the inner Q₁ and R₂ heads are given.