A mummified forearm of Djer or his wife was discovered by Egyptologist Flinders Petrie,[3] but was discarded by Émile Brugsch.

Jürgen von Beckerath in the Handbuch der ägyptischen Königsnamen (1999) translates the hieroglyphs of the name Djer as "Defender of Horus.

"[5] Although the Egyptian priest Manetho, writing in the third century BC, stated that Djer ruled for 57 years, modern research by Toby Wilkinson in Royal Annals of Ancient Egypt stresses that the near-contemporary and therefore, more accurate Palermo Stone ascribes Djer a reign of "41 complete and partial years.

The evidence for Djer's life and reign is:[8] The inscriptions, on ivory and wood, are in a very early form of hieroglyphs, hindering complete translation, but a label at Saqqarah may depict the First Dynasty practice of human sacrifice.

Manetho claimed that Athothes, who is sometimes identified as Djer, had written a treatise on anatomy that still existed in his own day, over two millennia later.