RIN-deficient fruits generated by CRISPR/Cas9 initiated partial ripening at a similar time to wild-type (WT) fruits but only 10% WT levels of carotenoids and ethylene were synthesised. RIN-deficient fruit never ripened completely, even when supplied with exogenous ethylene. The low amount of endogenous ethylene that they did produce was sufficient to enable ripening initiation and this could be suppressed by the ethylene perception inhibitor 1-MCP. The reduced ethylene production by RIN-deficient tomatoes was due to an inability to induce autocatalytic system-2 ethylene synthesis, a characteristic feature of climacteric ripening. Production of volatiles and transcripts of key volatile biosynthetic genes were also greatly reduced in the absence of RIN. In contrast, the initial extent and rates of softening in the absence of RIN were similar to WT fruits, although detailed analysis showed the expression of some cell wall modifying enzymes was delayed and others increased in the absence of RIN. These results support a model where RIN and ethylene, via ERFs, are required for full expression of ripening genes. Ethylene initiates ripening of mature green fruit, upregulates RIN expression and other changes, including system-2 ethylene production. RIN, ethylene and other factors are required for completion of the full fruit ripening program.