Penelitian ini bertujuan untuk: (1) mengetahui karakteristik performance assessment yang valid dan reliabel untuk mengukur practical skills IPA pada guided-PjBL, (2) mendeskripsikan practical skills IPA yang muncul pada guided-PjBL, dan (3) mengetahui peta practical skills IPA siswa SMP menggunakan performance assessment. Penelitian ini merupakan Research & Development dengan menggunakan model 4-D Thiagarajan, et al. (1974). Subjek uji coba adalah siswa kelas VII di SMPN 1 Wonosari, SMPN 4 Playen, dan SMPN 5 Ngawen.Teknik pengambilan data meliputi wawancara, angket, dan nontes. Instrumen pengambilan data meliputi pedoman wawancara, lembar angket, dan lembar observasi. Hasil penelitian ini yaitu performance assessment dalam bentuk lembar observasi dinyatakan valid dan reliabel. Practical skills IPAyang muncul pada guided-PjBL meliputi: merancang proyek; menggunakan termometer dan indikator universal; membaca hasil pengukuran suhu dan pH; membuat tabel; menentukan variabel bebas dan terikat; membuat grafik; mengetahui hubungan antar-variabel; dan membuat kesimpulan. Siswa pada sekolah kategori tinggi memiliki tingkat kemampuan practical skills paling tinggi bila dibandingkan dengan siswa pada sekolah kategori sedang dan rendah. Siswa pada sekolah kategori sedang memiliki tingkat kemampuan practical skills paling rendah.Kata Kunci: performance assessment, lembar observasi, guided-PjBL, practical skills IPA Developing Performance Assessment to Map Science Practical Skills on Guided-PjBL AbstractThis study aims to: (1)find out the characteristic of performance assessment that is valid and reliable to measure science practical skills on guided-PjBL, (2) describe science practical skills that appear on guided-PjBL, and (3) find out the map student’s science practical skills in junior high school to use performance assessment on guided-PjBL. This was a research and development study employing the development model by Thiagarajan et al. (1974).The tryout subjects were junior high school student in SMPN 1 Wonosari, SMPN 4 Playen, and SMPN 5 Ngawen. The data were collected through interviews, questionnaires, and nontests. The data collecting instruments included an interview guided, validation questionnaire sheets, and observation sheets. The result of the study was the product of performance assessment in observation sheet form was valid and reliable. Science practical skills that appear on guided-PjBL. included: designing project; using thermometre and universal indicator; reading temperature and pH measurement; creating table; defining independent-dependent variable; creating graph; find out relation between variable; and drawing conclusion. The students in the school with the high category have the highest science practical skills of the three schools. The students in the school with the low category have higher science practical skills than students in high grade school.Keywords: performance assessment, observation sheet, guided-PjBL, science practical skills