In the present paper, absolute matrix summability of infinite series is studied. A new theorem concerning absolute matrix summability factors, which generalizes a known theorem dealing with absolute Riesz summability factors of infinite series, is proved using almost increasing and δ-quasi-monotone sequences. Also, a result dealing with absolute Cesàro summability is given.

Keywords: summability factors, almost increasing sequences, absolute matrix summability, quasi-monotone sequences, infinite series, Ho¨lder inequality, Minkowski inequality.