Eventual consistency in NoSQL means that when all the service logic has been executed, the system is left in a consistent state. For achieving high availability, this concept is used in distributed systems. It gives a guarantee that, if new updates are not made to a given data item, then eventually all accesses to that item will return the last updated value. In NoSQL, it is provided in terms of BASE and RDMS are also known as ACID properties. Present NoSQL databases provide client applications with the guarantee of eventual consistency. Some NoSQL databases like- MongoDB and Cassandra are eventually consistent in some of the configurations.