Poly(ester amide) has attracted much attention because they demonstrate satisfactory mechanical performance, yet are biodegradable. Owing to the increasing depletion of fossil resources, we chose 1,4-butanediol, 1,10-decanediamine (DD), 1,10-sebacic acid, and itaconic acid (IA), which can be produced in large scale by fermentation of renewable resources, to synthesize a series of biobased poly(ester amide)s (BPEAs) by condensation polymerization. We used multiple monomers to suppress crystallization. The pyrrolidone rings formed between DD and IA increases the molecular spacing and the chain irregularity of BPEAs. The properties of BPEAs were tunable by adjusting the monomer ratio. The effect of DD content on the molecular weight, thermal stability, mechanical properties, and in vitro degradation of BPEAs was investigated. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43446.