His childhood name was Johann, which he changed to Gregor when he became a Priest. Johann was born in 1822 to peasant farmers in the Czech Republic part of Eastern Europe. The place of birth was a village called Heinzendorf, which is now called Hyncice. The area borders where Germany, Poland, and the Czech Republic come together.

The town of Heinzendorf occupies both sides of a stream that carves its way through the rolling countryside.  Most of the houses today, and then, had two stories with slate roofs. The people live in the town and work the farms in the countryside. At the time when Johann was born, the town had 102 families.

Johann was an only son and had four sisters. He was born in 1822.

Not much is known about Johann's childhood. Johann himself did not say much about it in his short autobiography, which was written in the third person (see the book by Olby).

We do know that Johann worked with his father a lot in the family orchard, which stimulated his interest in the things of nature. He learned to love growing plants and gardening, a love that he brought to his scientific research when he grew up.

Another thing that influenced his later life was his puzzlement about why he had a mixture of his parents' traits, but his sisters did not. Johann had the short stocky build of his father and the cheerfulness and language skills of his mother.  His elder sister was more like the father, both in appearance and disposition, while a younger sister was more like the mother.