The controversies about karma in dreams and its fruition have been discussed by the A ̅bhidharmikas of the Sarvastivadin School since the time of Sectarian Buddhism. A common agreement was that consciousness only creates Particularizing Karma rather than Directive Karma in dreams, and thus karma in dreams cannot direct sentient beings to commonality. The A ̅bhidharmikas of the Sarvastivadin School believe that dreams form an environment for the fruition of Vipāka-phala, and all karmas in dreams can affect consciousness and the Sendriya-kāya. When the Sendriya-kāya is affected, it is said that karma in dreams produces a Vipāka-phala in the real world. Hence, this dissertation presents the views of the A ̅bhidharmikas of the Sarvastivadin School which claim that karma in dreams come to fruition in both dreams and the real world, but are different. They also believe that the fruition of karma in dreams is relatively effortless since consciousness in dreams is ignorant and ambiguous. Based on the views listed above, this dissertation provides information on the perspective of Vijñapti-Only. Vijñapti-Only basically believes there is “no other real world beyond the consciousness”, which can be interpreted as “the sarva-dharma in the external world is the reflection of the internal consciousness”. Thus, this thesis focuses on the controversies regarding karma in dreams and its fruition from the perspective of Vijñapti-Only. In the philosophy of Vijñapti-Only, karma is also considered a system of setting hypothesis. It is believed that the seeds stored in the A ̅laya Consciousness lead to phenomena as a result of karmic impressions and the Two Habit Energies. The consciousness creates karma based on these phenomena and produces perfumations or impressions, which become the seeds stored in the A ̅laya Consciousness. This process is an endless cycle. Therefore, the fruition of karma depends on the consciousness and its present conditions. Consciousness is the subject which creates karma and its present conditions are the main factors that produce perfumations or impressions. However, according to Vijñapti-Only, both dreams and the outer world are reflections of consciousness, and the fruitions of karma in dreams should be no different from that in the real world. But in Vasubandhu’s Viṃśatikāvijñapti -mātratā-siddhiḥ , it is believed that consciousness is influenced during sleep, which leads to different fruitions. This dissertation’s contextual analysis shows that the “different fruitions” should be interpreted as “different karma fruitions in dreams and in the real world”, rather than “just karma fruition in the real world”. It is concluded from the study that based on the Vijñapti-Only of the Vijñaptimātratāsiddhi -śāstra, conscious impressions on karma in dreams are less because dreams are illusive. Consciousness in dreams is ignorant and ambiguous, and sentient beings have no true mind in dreams. As a result, the fruition of karma in dreams is relatively effortless, which proves the