• Erasmus Darwin I (1731-1802), the physician, poet, etc: grandfather of Charles Robert Darwin
• Erasmus Darwin II, also Erasmus Darwin the Younger (1759-1799), the son of Erasmus Darwin, brother of Robert Darwin, and uncle of Charles Robert Darwin
• Erasmus Alvey Darwin (Erasmus Darwin III) (1804–1881), grandson of Erasmus Darwin I, nephew of Erasmus Darwin II, son of Robert Darwin, brother of Charles Robert Darwin.
• Erasmus Darwin IV (1881-1915), son of Horace Darwin, grandson of Charles Robert Darwin, grandnephew of Erasmus Alvey Darwin, great-grandnephew of Erasmus Darwin II, great-great-grandson of Erasmus Darwin I. See his entry in the Commonwealth war graves database and his biography by his cousin Bernard Darwin.

See also:

• Erasmus Darwin House, house of Erasmus Darwin in Lichfield.
• Erasmus Darwin Barlow (1915-2005), great-great-great-grandson of Erasmus Darwin
• Erasmus Darwin Keyes (1810-1895), apparently unrelated.