The invention relates to a system (26) for changing the pitch of blades of at least one turbo machine rotor, comprising: a control means acting on a connecting mechanism (31) that is connected to theblades of the rotor and comprising a body (29) which is mobile in translation along a longitudinal axis with respect to a fixed body (28), at least one load-transfer bearing (34) mounted on the mobilebody and cooperating with the connecting mechanism, and means (60) for lubricating said bearing (34) comprising at least one lubricant duct (61) and extending radially above the fixed and mobile bodies, the duct comprising at least first and second tubular parts that are telescopic and slide coaxially with respect to one another, the first part being connected to said fixed body and the second part being connected to the mobile body, means for spraying lubricant in the bearing that are mounted on said mobile body and at least one lubricant supply conduit (75) mounted on the mobile body to connect the duct to said spraying means.