Decays $chi_{cJ}~(J=0,1,2)toomegaphi$ are studied using $(448.1pm2.9)times 10^{6} ~psi(3686)$ events collected with the BESIII detector in 2009 and 2012. In addition to the previously established $chi_{c0}toomegaphi$, first observation of $chi_{c1} to omega phi$ is reported in this paper. The measured product branching fractions are ${cal{B}}(psi(3686)togammachi_{c0})times{cal{B}}(chi_{c0}toomegaphi)=(13.83pm 0.70pm 1.01)times10^{-6}$ and ${cal{B}}(psi(3686)togammachi_{c1})times{cal{B}}(chi_{c1}toomegaphi)=(2.67pm 0.31pm 0.27)times10^{-6}$, and the absolute branching fractions are ${cal{B}}(chi_{c0}toomegaphi)=(13.84pm 0.70pm 1.08)times10^{-5}$ and ${cal{B}}(chi_{c1}toomegaphi)=(2.80pm 0.32pm 0.30)times10^{-5}$. We also find a strong evidence for $chi_{c2}toomegaphi$ with a statistical significance of 4.8$sigma$, and the corresponding product and absolute branching fractions are measured to be ${cal{B}}(psi(3686)togammachi_{c2})times{cal{B}}(chi_{c2}toomegaphi)=(0.91pm0.23pm0.12)times10^{-6} $ and ${cal{B}}(chi_{c2}toomegaphi)=(1.00pm0.25pm0.14)times10^{-5}$. Here, the first errors are statistical and the second ones systematic.
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