diff --git a/bits/87_read.js b/bits/87_read.js
index fe0e8eb..15bcfd6 100644
--- a/bits/87_read.js
+++ b/bits/87_read.js
@@ -116,6 +116,7 @@ function readSync(data/*:RawData*/, opts/*:?ParseOpts*/)/*:Workbook*/ {
 		case 0x7B: if(n[1] === 0x5C && n[2] === 0x72 && n[3] === 0x74) return rtf_to_workbook(d, o); break;
 		case 0x0A: case 0x0D: case 0x20: return read_plaintext_raw(d, o);
 		case 0x89: if(n[1] === 0x50 && n[2] === 0x4E && n[3] === 0x47) throw new Error("PNG Image File is not a spreadsheet"); break;
+		case 0x25: if(n[1] === 0x50 && n[2] === 0x44 && n[3] === 0x46) throw new Error("PDF File is not a spreadsheet"); break;
 		case 0x08: if(n[1] === 0xE7) throw new Error("Unsupported Multiplan 1.x file!"); break;
 		case 0x0C:
 			if(n[1] === 0xEC) throw new Error("Unsupported Multiplan 2.x file!");