We proceed to study Yang-Baxter deformations of the AdS 5 ×S 5 superstring with the classical Yang-Baxter equation. We make a general argument on the supercoset construction and present a formula to describe the dilaton in terms of classical rmatrices. The supercoset construction is explicitly performed for some classical rmatrices and the full backgrounds including the Ramond-Ramond (R-R) sector and dilaton are derived. Within the class of abelian r-matrices, the perfect agreement is shown for well-known examples including gravity duals of non-commutative gauge theories, γ-deformations of S 5 and Schrödinger spacetimes. It is remarkable that the supercoset construction works well, even if the resulting backgrounds are not maximally supersymmetric. In particular, three-parameter γ-deformations of S 5 and Schrödinger spacetimes do not preserve any supersymmetries. As for non-abelian r-matrices, we will focus upon a specific example. The resulting background does not satisfy the equation of motion of the Neveu-Schwarz-Neveu-Schwarz (NS-NS) two-form becauseThis coset enjoys the Z 4 -grading property and ensures classical integrability [9] (for a nice review, see [10]). The integrability plays an important role in checking the conjectured relation in AdS/CFT (for a comprehensive review, see [11]). By employing the Yang-Baxter deformation, Delduc, Magro and Vicedo constructed the classical action of a q-deformed AdS 5 ×S 5 superstring [12]. This deformation comes from the classical r-matrix of Drinfel'd-Jimbo type satisfying the mCYBE [13]. The string-frame metric and Neveu-Schwarz-Neveu-Schwarz (NS-NS) two-form were derived by Arutyunov, Borsato and Frolov [14]. Then they performed the supercoset construction and derived the remaining sector [15] (for earlier attempts, see [16, 17]). As a result, the full background does not satisfy the equations of motion of type IIB supergravity, although it is related to a complete solution [18] via T-dualities apart from the dilaton part. In particular, the dilaton cannot be separated so that the Ramond-Ramond (R-R) flux should satisfy the Bianchi identity. Recently, Arutyunov et al. proposed an exciting conjecture that type IIB supergravity itself would get deformed, for example, the definition of R-R field strength may be modified [19]. This "modified gravity conjecture" may be connected to our result presented here.One may also consider Yang-Baxter deformations of the AdS 5 ×S 5 superstring with classical r-matrices satisfying the homogeneous CYBE [20]. A strong advantage in this case is that partial deformations of AdS 5 ×S 5 are possible. In fact, for well-known backgrounds including gravity duals of noncommutative gauge theories [21,22], γ-deformations of S 5 [23,24],