{{Chembox new
|   Name = Ácido oxaloacético
|   ImageFile = Oxaloacetic acid.png
|   ImageName = 
|   IUPACName = Ácido 2-oxobutanodióico
|   OtherNames = Ácido cetosuccínico
| Section1 = {{Chembox Identifiers
|   CASNo = 328-42-7
|   EINECS = 206-329-8
|   SMILES = OC(C(CC(O)=O)=O)=O
  }}
| Section2 = {{Chembox Properties
|   Formula = C<sub>4</sub>H<sub>4</sub>O<sub>5</sub>
|   MolarMass = 132.07 g/mol
|   MeltingPt = 161 °C
|   Density = ? g/cm<sup>3</sup>
  }}
}}
O '''ácido oxaloacético''' é um base conjugada é chamada de '''oxaloacetato'''.

O oxaloacetato é um composto intermediário no malato, catalisado pela enzima malato desidrogenase e reage com o acetil-CoA para formar citrato, catalisado, por sua vez, pela citrato sintase.

O oxaloacetato também se forma no CO<sub>2</sub> com o piruvato via reação anaplerótica.

A forma de pontos de fusão (152 °C ''cis'', 184 °C ''trans''). Sua fumarase A da ''E. coli'' catalisa a conversão da forma cetona para a forma enol do oxaloacetato.

{{Chembox new
|   Name = Oxaloacetic acid
|   ImageFile = Oxaloacetic acid.png
|   ImageName = 
|   IUPACName = Oxobutanedioic acid
|   OtherNames = Oxaloacetic acid<br />Oxalacetic acid<br />Oxosuccinic acid
| Section1 = {{Chembox Identifiers
|   CASNo = 328-42-7
|   EINECS = 206-329-8
|   SMILES = OC(C(CC(O)=O)=O)=O
  }}
| Section2 = {{Chembox Properties
|   Formula = C<sub>4</sub>H<sub>4</sub>O<sub>5</sub>
|   MolarMass = 132.07 g/mol
|   MeltingPt = 161 °C
|   Density = ? g/cm<sup>3</sup>
  }}
| Section4 = {{Chembox Thermochemistry
|   DeltaHf = -943.21 kJ/mol
|   DeltaHc = -1205.58 kJ/mol
  }}
}}
'''Oxaloacetic acid''' is an malate, catalysed by CO<sub>2</sub> with PEP Carboxykinase.  It can arise from anaplerotic reaction.

The pK<sub>a</sub> value of 13.02.  The ''E. coli'' catalyses the conversion between the keto and enol forms.

Oxaloacetate is unstable in solution, decomposing to pyruvate by decarboxylation over a period of hours (room temperature) or days (0 °C). Refrigerated storage of the solid is therefore recommended.

thumb|150px|left|Relationship of oxaloacetic acid, malic acid, and aspartic acid