本文以CMARC3與MARC 21的指標與代碼為探討對象。指標部分，首先分別探討兩種MARC指標的功能與異同，說明轉換MARC時關於指標需留意的問題，例如指標與分欄互轉、指標與代碼互轉等，進而提出需思考在未來自動化系統中，指標是否仍應具備指示檢索的功能。代碼方面，先說明在兩種MARC中使用代碼標示資料內容的欄位，各自如何以代碼呈現書目中特定的意義；之後提出數項關於代碼在著錄使用及進行不同MARC之間代碼轉換的重要議題分別討論，包括關於語文代碼、國家代碼、中國特殊資料代碼、分類及標題系統代碼等，最後提出未來建議 MARC 21增補或臺灣圖資界應考慮增訂的代碼。

This paper compares CMARC3 and MARC 21 indicators and codes to present important concepts and contents of these two MARCs in indicators and codes. About indicators, drescibing the functions and differences of indicators of these two MARCs, is in order to explain the conversion principle between indicators, subfields and codes. Then mention the necessity of rethinking the information retrival functions should be required by data indicators or system parameter. About codes, compare how the data be coded in important issues including cataloging language, publishing country, classification system, etc. in two MARCs. Especially for Chinese records, some meaningful codes contents should be preserved by program processing. Conclusions and recommendations are given eventually that several codes for Taiwan bibliographic records should be disscused wildly and suggest to LC.