馬偕在北臺灣的傳教工作頗為成功。至1883年時已經看見豐碩的成果，尤其是在宜蘭地區的噶瑪蘭族部落，成績更是顯著。根據馬偕自己的記錄，超過2000多名噶瑪蘭拋棄了原來祭拜的偶像改信基督教。1886年，馬偕提到他在東海岸花蓮已經有18個聚會所，當地已有1138人受洗。雖然1884至1885年中法戰爭期間，因為台灣民眾仇外情緒燒毀了7間馬偕蓋的教堂，後來獲得劉銘傳給的賠償金，重蓋了更加宏偉的「賠償教會」。至1901年馬偕過世前，總計建立了超過90間教堂，信徒超過4,000名。；是宜蘭地區就有30多個噶瑪蘭村落設立教會，現今還有不少噶瑪蘭人姓「偕」，也是當時受到馬偕的影響。

Mackay’s mission in Taiwan was extremely successful. It was particularly effective among some indigenous groups, such as the Kavalan people, where Mackay recorded that “Upward of 2,000 have thrown away their idols and wish to follow the Lord of Hosts.” (Mackay p. 43–44) In 1886, Mackay visited 18 stations along the east coast around Hualien, where he baptized 1,138 inhabitants. (Mackay p. 44) During the French blockade of Taiwan in 1884–1885, a widespread outbreak of anti-Christian movement occurred that led to the burning of seven mission chapels. Nevertheless, in the course of Mackay’s whole missionary career in Taiwan, more than 80 churches and 4,000 converts existed.