There are following disadvantages of using LINQ:

• LINQ is not good to write complex queries like SQL.
• If you have done some changes in your query, you have to recompile it and redeploy its dll to the server.
• Small data sets will take longer to build the query than execute.
• When queries are moved from sql to application side, joins are very slow.
• DBML concurrency issues.
• Hard to understand advance queries using Expressions.