大多数学校都要求申请人提供二至三封教授推荐信。有力的推荐是录取的重要条件之一。推荐信要客观、公正、切忌流于形式，内容空洞，要与申请人的其它材料(如成绩单)等相符。推荐信也应注意格式、文法等。因为向来有“名师出高徒”之说。推荐信的格式与一般书信基本相同。有信头，发信日期，收信人姓名，称呼，正文，信尾谦称，签名，推荐人姓名，职称及工作单位等部分。但推荐信还应着重以下方面：
1. 为了便于校方查阅，必须提到被推荐者的全名。
2. 必须交待与被推荐者的认识期间(何时开始认识或认识多久)，认识程度(偶尔见面或密切接触)及关系(师生关系，上下级关系，同事等)。
3. 对被推荐者的优点介绍及评价，这是推荐信的核心。主要包括被推荐者的天赋，学习成绩，研究能力，工作经验，学习精神，组织能力，品行及个性方面。
4. 必须表明推荐人的态度，是极力推荐还是有保留地推荐。
最近一些学校出于各种原因，设计了推荐表格，由推荐人填写，但其主要内容也和推荐信涉及的相同。
范例1 计算机教授推荐信
At the request of Mr. Xizhen Chen, my former student in the Department of Computer Science, Beijing Univ. of Sciences, I am glad to write this letter furnishing my evaluation of his academic aptitude for your reference. Mr. Chen is interested in your graduate program in Computer Science.
I came to know him in September 1987 when Mr. Chen enrolled in my class on FORTRAN IV Programming, a three semesters' course. In the class he was one of the most outstanding students. At the semester final he earned a high grade of 81, which should be "A" according to our grading system. I also found him good at other studies.
After the class, he had personal talks with me several times. He indicated a great interest in computer hardware, In my opinion, Mr. Chen has a potential in Computer Science, which can be further developed.
In view of his previous achievements in this College, I am firmly convinced that Mr. Chen will make a successful graduate student. Your favorable consideration of his admission will be highly appreciated.