Background:
In this study, we aimed at examining Indonesian In-Service primary Teachers’ Mathematics Content Knowledge (MCK) and Mathematics Pedagogical Content Knowledge (MPCK) for teaching ratio and proportion. The instruments were administered to 271 in-service primary teachers with various education background

Materials and methods:
There were three underlined factors on MCK and MPCK instrument classified by item analysis and factor analysis. Three teachers’ categories (Good, Middle, and Low) were established by cluster analysis methodology

Results:
The most teachers’ challenge on MCK was figural representation. For MPCK, Indonesian teachers need more opportunity to learn the factor of Knowing students conceptual understanding.

Conclusions:
The state of teachers’ MCK and MPCK and related components are worthy to suggest the design of Indonesian In-service Teachers Professional Development Program.