A straightforward method for the preparation of metallo carbosiloxanes of type Si(OCH 2 CH 2 CH 2 SiMe 2 [OCH 2 PPh 2 M(CO) n ]) 4 (n=3, M=Ni, 7a; n=4, M=Fe, 7b; n=5: M=Mo, 7c; M=W, 7d), Si(OCH 2 CH 2 CH 2 SiMe[OCH 2 PPh 2 Ni(CO) 3 ] 2 ) 4 (8) and Me 2 Si(OCH 2 CH 2 CH 2 SiMe[OCH 2 PPh 2 Ni(CO) 3 ] 2 ) 2 (11) is described. The reaction of Si(OCH 2 CH 2 CH 2 SiMeXCl) 4 (1: X=Me, 2: X=Cl) or Me 2 Si(OCH 2 CH 2 CH 2 SiMeCl 2 ) 2 (9) with HOCH 2 PPh 2 (3) produces Si(OCH 2 CH 2 CH 2 SiMe 2 (OCH 2 PPh 2 )) 4 (4), Si(OCH 2 CH 2 CH 2 SiMe(OCH 2 PPh 2 ) 2 ) 4 (5) or Me 2 Si(OCH 2 CH 2 CH 2 SiMe(OCH 2 PPh 2 ) 2 ) 2 (10) in presence of DABCO. Treatment of the latter molecules with Ni(CO) 4 (6a), Fe 2 (CO) 9 (6b), M(CO) 5 (Thf) (6c: M=Mo; 6d: M=W), respectively, gives the title compounds 7a–7d, 8 and 11 in which the PPh 2 groups are datively bound to a 16-valence-electron metal carbonyl fragment.The formation of analytical pure and uniform branched and dendritic metallo carbosiloxanes is based on elemental analysis, and IR, 1 H, 13 C{ 1 H}, 29 Si{ 1 H} and 31 P{ 1 H} NMR spectroscopic studies. In addition, ESI-TOF mass spectrometric studies were carried out.