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We report the detection of the Zeeman effect in the 44 GHz Class I methanolmaser line toward the star forming region DR21(OH). In a 219 Jy/beam masercentered at an LSR velocity of 0.83 km s$^{-1}$, we find a 20-$\sigma$detection of $zB_{\text{los}} = 53.5 \pm 2.7$ Hz. If 44 GHz methanol masers areexcited at $n \sim 10^{7-8}$ cm$^{-3}$, then the $B~vs.~n^{1/2}$ relation wouldimply from comparison with Zeeman effect detections in the CN($1-0$) linetoward DR21(OH) that magnetic fields traced by 44 GHz methanol masers inDR21(OH) should be $\sim$10 mG. Together with our detected $zB_{\text{los}} =53.5$ Hz, this would imply that the value of the 44 GHz methanol Zeemansplitting factor $z$ is $\sim$5 Hz mG$^{-1}$. Such small values of $z$ wouldnot be a surprise, as the methanol molecule is non paramagnetic, like H$_2$O.Empirical attempts to determine $z$, as demonstrated, are important becausecurrently there are no laboratory measurements or theoretically calculatedvalues of $z$ for the 44 GHz methanol transition. Data from observations of alarger number of sources are needed to make such empirical determinationsrobust.

The Zeeman Effect in the 44 GHz Class I Methanol Maser Line toward DR21(OH)