The two previously unseen pictures turned up in Europe and are expected to raise £20,000 between them.
Hitler drew them in the early 1900s when he was based in Vienna and was practising various styles so that he might win a place at art college.
The picture of the elderly woman's face is similar to photographs of his mother and shows a lined and world-weary visage.
It was drawn in 1908 - the year after she died from cancer. The closed eyes might signify her demise.
The contrasting nude drawn a year earlier is a young, pert and attractive figure with breasts obscured by an arm and a blank face.
They give little insight into the mind of the mad dictator because his character changed so much during the First World War.
His other paintings from the time were more likely to have an architectural element or a pleasant landscape scene.
Richard Westwood-Brookes, who is selling the art, said: "The nude interestingly doesn't have a face drawn in.
"It's not because he couldn't do faces because he drew the other one of the elderly woman who might be his mother.
"Perhaps there is no face because Hitler saw people just as inanimate objects.
"However, it is actually quite a tender drawing in red and brown crayon. It measures 10x7 inches and has probably been torn from a sketch book.
"At the time he was looking to get into art college and was experimenting with various styles and painting a nude would have been a required skill.
"It's been suggested that the sketch of the elderly woman with her eyes closed might be his mother who had just died.
"It is sketched in charcoal and measures 12x8 inches and is not a bad drawing.
"Hitler at this time he drew these was a different person from that after the First World War."
The sale takes place in Ludlow, Shropshire, on March 2.
