For an ordered groupoid $G$, we denote by $G^0$ the ordered groupoid arising from $G$ by the adjunction of a zero element. We first prove the following: If $S$ is an ordered groupoid, then there exists a proper prime ideal of $S$ if and only if there exists and ordered group $G$ and a mapping $f$ of $S$ onto $G^0$ which is a homomorphism. The following question arises: Given an ordered groupoid $S$ under what conditions there exists and ordered group $G$ such that $S$ is isomorphic to $G^0$ ? We prove the following: If $S$ is an ordered groupoid with a zero element $\theta$ such that $S\backslash \{\theta \}$ is a subgroup of $S$, then there exists an ordered group $G$ such that $S$ is isomorphic to $G^0$. The converse statement also holds: If $S$ is an ordered groupoid and $G$ an ordered group such that $S$ is isomorphic to $G^0$, then there exists a zero element $\theta$ of $S$ such that $S\backslash \{\theta \}$ is a subgroup of $S$.