在分子生物学中，起始点识别复合物（origin recognition complex, ORC）是指一种真核生物体内的含有多个亚基、与DNA结合的复合物。它与DNA通过一种ATP依赖性的方式相连，使得DNA复制得以启动。该复合物的几个亚基分别由ORC1、ORC2、ORC3、ORC4、ORC5、ORC6基因编码。起始点识别复合物不仅在真核生物DNA复制期间存在，在整个细胞周期的其余时段也与复制起点结合。起始点识别复合物对DNA复制的启动来说不可或缺。与复制起点结合的起始点识别复合物使得复制前复合物（pre-replication complex, pre-RC）得以组装。复制前复合物的组分包括Cdc6、Tah11(亦称Cdt1），以及MCM2-MCM7复合物。复制前复合物在G1期的组装对于S期的DNA复制前的DNA复制许可至关重要。不经过许可，DNA复制就无法进行。周期素依赖性蛋白激酶Cdc28能磷酸化Orc2、Orc6、Cdc6，以调节DNA复制的起始（包括封锁G2/M期的复制再启动），进而达到调节细胞周期的目的。

In molecular biology, origin recognition complex (ORC) is a multi-subunit DNA binding complex (6 subunits) that binds in all eukaryotes in an ATP-dependent manner to origins of replication. The subunits of this complex are encoded by the ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6 genes. ORC is a central component for eukaryotic DNA replication, and remains bound to chromatin at replication origins throughout the cell cycle. ORC directs DNA replication throughout the genome and is required for its initiation. ORC bound at replication origins serves as the foundation for assembly of the pre-replication complex (pre-RC), which includes Cdc6, Tah11 (aka Cdt1), and the Mcm2-Mcm7 complex. Pre-RC assembly during G1 is required for replication licensing of chromosomes prior to DNA synthesis during S phase. Cell cycle-regulated phosphorylation of Orc2, Orc6, Cdc6, and MCM by the cyclin-dependent protein kinase Cdc28 regulates initiation of DNA replication, including blocking reinitiation in G2/M phase.