Extracts using chloroform, methanol-acetone, aqueous, and an acetogenin fraction obtained from soursop fruit pulp were analyzed by measuring total soluble phenolic compounds and antioxidant activities using the assays: scavenging 1,1-diphenyl-2-picrylhydrazil (DPPH) radical, 2,20-Azinobis-3-ethylbenzotiazoline-6-sulfonic acid (ABTS) radical, reducing power, nitric oxide radical, and total antioxidant capacity. Methanol-acetone extract had higher total soluble phenolic compounds (3.24-3.95 g/100 g DW), antioxidant capacity by DPPH (47.9 mmol TE/g DW) and total antioxidant capacity (221.96 μg α-tocopherol equivalent). However, analysis by ABTS, reducing power and nitric oxide radical methods also showed high antioxidant capacity in aqueous extract. Chloroform extract and acetogenin fraction had higher antioxidant capacity when using the reducing power method (23.85 and 21.77 μM AA equivalent, respectively), and was higher than in aqueous extract. Our results suggest that soursop pulp is a good source of antioxidants and has acetogenins, making the fruit a potentially important functional food.