A mixer assembly for mixing an injected reductant with an exhaust gas output from a combustion engine comprises a mixer housing including a wall defining an exhaust passageway having a longitudinal axis. A tubular swirling device housing extends along a first axis substantially transverse to the longitudinal axis. The tubular swirling device includes a plurality of openings through which exhaust gas enters. The exhaust gas within the tubular swirling device swirls about the first axis and exits at an outlet end of the tubular swirling device. A mixing plate is positioned immediately downstream of the tubular swirling device and includes apertures through which the exhaust gas exiting the outlet end of the tubular swirling device flows. The mixing plate swirls the exhaust about a second axis extending parallel to the longitudinal axis.