A geochemical study on clinopyroxenes in plutonic and volcanic sequences of the Middle Proterozoic ophiolites from Sichuan Province, China, has been undertaken by microprobe analysis The sympathetic variations of Fe/Mg ratio between clinopyroxenes and their host rocks suggest that the clinopyroxene compositions can be used as a reliable indicator of the parent magma type. AI in clinopyroxenes correlates negatively with Si and positively with Ti. Δ[Ti]/Δ[Al] and Δ[Si]/Δ[Al] ratios (calculated from linear regression analysis on the cation numbers in structural formula) are very similar in plutonic (0.30 and -0.78, respectively) and volcanic (0.32 and -0.76, respectively) rocks, indicating a same mode of substitution ([0.6 ± 0.04] Ti + 2 Al <==> M²⁺ + [1.6 ± 0.04]) Si) and a co-magmatic origin for the two sequences. In spite of an enrichment in Al and Ti, caused by the high cooling rate in some samples from the volcanic sequence, the overall chemical compositions of the analyzed clinopyroxenes display a tholeiitic affinity. These compositions are also comparable, in particular, to those of clinopyroxenes in plutonic and basaltic rocks of typical high-Ti Phanerozoic ophiolites, and even to those of clinopyroxenes from modern mid-ocean ridge rocks. This is in good agreement with the conclusions obtained from our petrographic and bulk geochemical studies on the elements resistant to alteration and metamorphism. The fact that the clinopyroxenes in the most Ti-enriched ferrogabbros are relatively poor in this element reveals that the high-Ti ophiolite magma would have reached, by differentiation, a stage of enrichment not only in Fe and Ti, but also in Si0₂; thus, instead of entering the chlinopyroxene structure, Ti would crystallize as titanomagnetite. This work provides some interesting geochemistry indications supporting the hypothesis that the petrogenetic and geodynamic processes accepted for the Phanerozoic ophiolites can also be applied to those of the Middle Proterozoic.