Phosphoinnelite, an analogue of innelite with P > S, has been found in a peralkaline pegmatite vein crosscutting calcite carbonatite at the phlogopite deposit, Kovdor pluton, Kola Peninsula. Cancrinite (partly replaced with thomsonite-Ca), orthoclase, aegirine-augite, pectolite, magnesioarfvedsonite, golyshevite, and fluorapatite are associated minerals. Phosphoinnelite occurs as lath-shaped crystals up to 0.2 × 1 × 6 mm in size, which are combined typically in bunch-, sheaf-, and rosettelike segregations. The color is yellow-brown, with vitreous luster on crystal faces and greasy luster on broken surfaces. The mineral is transparent. The streak is pale yellowish. Phosphoinnelite is brittle, with perfect cleavage parallel to the {010} and good cleavage parallel to the {100}; the fracture is stepped. The Mohs hardness is 4.5 to 5. Density is 3.82 g/cm 3 (meas.) and 3.92 g/cm 3 (calc.). Phosphoinnelite is biaxial (+), α = 1.730, β = 1.745, and γ = 1.764, 2V (meas.) is close to 90 ° . Optical orientation is Z^c ~ 5 ° . Chemical composition determined by electron microprobe is as follows (wt %): 6.(PO 4 ,SO 4 ) 2 (O,F) 3 . The mineral is triclinic, space group P or P 1. The unit cell dimensions are a = 5.38, b = 7.10, c = 14.76 Å; α = 99.00 ° , β = 94.94 ° , γ = 90.14 ° ; and V = 555 Å 3 , Z = 1. The strongest lines of the X-ray powder pattern [ d , Å in ( I )( hkl )] are: 14.5(100)(001), 3.455 (40)(103), 3.382(35)( ), 2.921(35)(005), 2.810(40)( ), 2.683(90)(200, ), 2.133(80)( ), 2.059(40)(204, , 221), 1.772(30)( , , , ). The infrared spectrum is demonstrated. An admixture of P substituting S has been detected in the innelite samples from the Inagli pluton (South Yakutia, Russia). An innelite-phosphoinnelite series with a variable S/P ratio has been discovered. The type material of phosphoinnelite has been deposited at the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.