This case series describes four cases of concomitant dermoid sinus and spina bifida in a Chinese crested dog, two Swedish vallhunds and a Burmese cat. The diagnosis was confirmed by computed tomography, computed tomography fistulography and pathology. Two dogs that showed abnormalities during neurological examination underwent magnetic resonance imaging. One of them had imaging findings interpreted as syringohydromyelia. All the dogs underwent surgery and the outcome was considered good in all the cases. Based on clinical and pathological examination as well as diagnostic imaging findings, two of the dermoid sinuses were classified as type IV, and two of them showed a previously unreported type of dermoid sinus. This new type is suggested here as type VI.