The title compound, C(20)H(32)N(5)O(8)P·0.5C(4)H(6)O(4), is composed of two 9-{2-[bis-(pivaloyloxymeth-oxy)phosphinylmeth-oxy]eth-yl}adenine, commonly known as adefovir dipivoxil (AD), mol-ecules linked to the carb-oxy-lic acid groups of succinic acid (SA). The asymmetric unit contains one mol-ecule of AD and half a mol-ecule of SA, which sits on an inversion center. Both adenine units in the two AD mol-ecules make AD-SA N-H⋯O and SA-AD O-H⋯N hydrogen bonds to SA. In addition, the inter-molecular AD-AD N-H⋯O-P hydrogen bond serves to stabilize the cocrystal. There is also a π-π stacking inter-action [inter-planar spacing 3.34 (19) Å] between adjacent inversion-related adenine groups.