The transport of 2-oxoglutarate and l-malate into the sucrose impermeable space of pea chloroplasts has been studied by silicone oil centrifugal filtration. The inhibition of transport of these dicarboxylates has been shown to be markedly different in the presence of the alternative dicarboxylate. The suggestion is made that at least two carriers are involved in the transport of 2-oxoglutarate with similar Km values of 0–20 mm for this substrate. l-Malate inhibited 2-oxoglutarate transport with a pseudo Ki value of 0–76 mm. l-Malate uptake was found to have a Km value of 0–29 mM and its uptake appeared to be inhibited, mainly competitively, by 2-xoglutarate with a Ki value of 0–2 mm.