While carbon monoxide (CO) gas has been extensively applied in the bulk chemical industry, its intrinsic properties such as high toxicity, flammability, and special equipment requirement for handling, limit its utilization in organic synthesis, fine chemical industry and academia. Recently, considerable effort has been devoted to the development of CO surrogates to avoid the direct use of carbon monoxide gas. Among the various CO surrogates, formic acid and formaldehyde, have a broad range of applications in organic synthesis. The direct carbonylation with formic acid (HCOOH) and formaldehyde (HCHO) represents one of the most atom-economical substitutes owing to their high weight percentage of CO. In this review, the potential roles of both formic acid and formaldehyde in transition-metal catalyzed carbonylation reactions are discussed. In order to understand these transfer carbonylation reactions, the mechanistic rationale for representative examples is also provided.