A monoazo compound represented by the following formula in a free acid form, ##STR1## wherein A is phenylene unsubstituted or substituted with methyl, methoxy, chloro, carboxy or sulfo, or naphthylene unsubstituted or substituted with sulfo, R.sub.1 and R.sub.2 are independently hydrogen, chloro, methyl, nitro, carboxy or sulfo, excepting the case where both R.sub.1 and R.sub.2 are hydrogen, and X is --CH.dbd.CH.sub.2 or --CH.sub.2 CH.sub.2 Y in which Y is a splittable group by the action of an alkali, which is useful for dyeing or printing fiber materials in a deep red color, and an aqueous liquid product of which is stable chemically and physically, even when stored for a long period of time.